v3.7.0.1
Restructuring (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Mar. 31, 2017
Dec. 31, 2017
Dec. 31, 2016
Restructuring Cost and Reserve [Line Items]      
Restructuring expenses $ 24    
Restructuring Reserve 21   $ 0
Employee Separation Costs      
Restructuring Cost and Reserve [Line Items]      
Restructuring expenses 21    
Restructuring Reserve 21   $ 0
Relocation of European Headquarters [Member]      
Restructuring Cost and Reserve [Line Items]      
Restructuring reserve, additional restructuring costs $ 24    
Minimum | Scenario, Forecast [Member]      
Restructuring Cost and Reserve [Line Items]      
Restructuring expenses   $ 5  
Maximum | Scenario, Forecast [Member]      
Restructuring Cost and Reserve [Line Items]      
Restructuring expenses   $ 10