Annual and transition report of foreign private issuers pursuant to Section 13 or 15(d)

Operating Segment Information and Concentrations of Risk - Summary of Geographical Information 2 (Detail)

v3.20.1
Operating Segment Information and Concentrations of Risk - Summary of Geographical Information 2 (Detail)
$ in Millions, $ in Millions
 1 Months Ended 12 Months Ended
Dec. 31, 2017
USD ($)
Dec. 31, 2017
AUD ($)
Mar. 31, 2020
USD ($)
Mar. 31, 2019
USD ($)
Mar. 31, 2018
USD ($)
Segment Reporting Information [Line Items]          
Research and development costs     $ 32.8 $ 37.9 $ 33.3
Selling, general and administrative expenses     415.8 403.6 311.3
Asbestos adjustments $ (43.6) $ (56.8) (58.2) (22.0) (156.4)
AICF SG&A expenses     1.7 (1.5) (1.9)
Net interest (income) expense     (54.4) (50.1) (29.5)
Impairment of Property, Plant & Equipment     64.5 9.1 0.7
Right-of-use assets     11.2    
Intangible assets     1.4    
Inventories     2.9    
Goodwill     0.2 4.6  
Asset Retirement Obligations     5.8    
Other     1.2    
Asset impairments     84.4 15.9 0.0
Cost of Sales          
Segment Reporting Information [Line Items]          
Other     2.8 0.4 0.7
Property, Plant and Equipment          
Segment Reporting Information [Line Items]          
Impairment of Property, Plant & Equipment     61.7    
Disposed of by Sale | Fontana Building | Buildings          
Segment Reporting Information [Line Items]          
Gain from disposition     0.0 0.0 3.4
General Corporate          
Segment Reporting Information [Line Items]          
Asbestos adjustments     58.2 (22.0) (156.4)
Assets held for sale     0.4    
Value of Asbestos-related assets     443.9 486.8  
Right-of-use assets     0.0    
Intangible assets     1.4    
Inventories     0.0    
Goodwill     0.0    
Asset Retirement Obligations     0.0    
Other     0.0    
Asset impairments     1.4    
General Corporate | Property, Plant and Equipment          
Segment Reporting Information [Line Items]          
Impairment of Property, Plant & Equipment     0.0    
North America Fiber Cement          
Segment Reporting Information [Line Items]          
Research and development costs     5.3 6.5 6.1
Impairment of Property, Plant & Equipment     44.0 3.0 0.7
Right-of-use assets     0.0    
Intangible assets     0.0    
Inventories     0.0    
Goodwill     0.0    
Asset Retirement Obligations     0.0    
Other     0.0    
Asset impairments     41.2 2.6  
North America Fiber Cement | Cost of Sales          
Segment Reporting Information [Line Items]          
Other     2.8    
North America Fiber Cement | Property, Plant and Equipment          
Segment Reporting Information [Line Items]          
Impairment of Property, Plant & Equipment     41.2    
Asia Pacific Fiber Cement          
Segment Reporting Information [Line Items]          
Research and development costs     1.8 2.1 1.8
Impairment of Property, Plant & Equipment     15.0 0.0 0.0
Right-of-use assets     11.2    
Intangible assets     0.0    
Inventories     2.9    
Goodwill     0.2    
Asset Retirement Obligations     5.8    
Other     1.2    
Asset impairments     36.3    
Asia Pacific Fiber Cement | Other liabilities - non-current          
Segment Reporting Information [Line Items]          
Asset Retirement Obligation     8.0    
Asia Pacific Fiber Cement | Property, Plant and Equipment          
Segment Reporting Information [Line Items]          
Impairment of Property, Plant & Equipment     15.0    
Europe Building Products          
Segment Reporting Information [Line Items]          
Research and development costs     1.7 2.6 0.0
Impairment of Property, Plant & Equipment     5.5 0.0 0.0
Right-of-use assets     0.0    
Intangible assets     0.0    
Inventories     0.0    
Goodwill     0.0 0.0  
Asset Retirement Obligations     0.0    
Other     0.0    
Asset impairments     5.5    
Europe Building Products | Property, Plant and Equipment          
Segment Reporting Information [Line Items]          
Impairment of Property, Plant & Equipment     5.5    
Research and Development          
Segment Reporting Information [Line Items]          
Research and development costs     24.0 26.7 25.4
Selling, general and administrative expenses     3.0 2.3 2.4
AICF Funding          
Segment Reporting Information [Line Items]          
Net interest (income) expense     1.4 2.0 1.9
Asia Pacific          
Segment Reporting Information [Line Items]          
New Zealand weathertightness claims (expense)/ benefit     1.9 3.3 0.0
Goodwill     0.2 0.0  
Other Businesses          
Segment Reporting Information [Line Items]          
Impairment of Property, Plant & Equipment     0.0 6.1 0.0
Goodwill     0.0 4.6  
Asset impairments       6.1  
Other Businesses | Operating Segments          
Segment Reporting Information [Line Items]          
Assets held for sale     5.8    
Assets disposed of     5.4    
Fermacell          
Segment Reporting Information [Line Items]          
Acquisition costs     0.0 0.0 $ 10.0
Transaction and integration related costs     $ 13.7 21.8  
Inventory fair value adjustment       7.3  
Goodwill | North America Fiber Cement          
Segment Reporting Information [Line Items]          
Asset impairments       0.0  
Goodwill | Other Businesses          
Segment Reporting Information [Line Items]          
Asset impairments       4.6  
Property, Plant and Equipment | North America Fiber Cement          
Segment Reporting Information [Line Items]          
Asset impairments       2.6  
Property, Plant and Equipment | Other Businesses          
Segment Reporting Information [Line Items]          
Asset impairments       6.1  
Finite-Lived Intangible Assets | North America Fiber Cement          
Segment Reporting Information [Line Items]          
Asset impairments       0.4  
Finite-Lived Intangible Assets | Other Businesses          
Segment Reporting Information [Line Items]          
Asset impairments       $ 2.2