v3.19.3.a.u2
Fair Value Measurement - Nonrecurring (Details) - Fair Value, Measurements, Nonrecurring [Member] - USD ($)
$ in Millions
1 Months Ended 3 Months Ended
Nov. 30, 2019
May 31, 2019
Dec. 31, 2019
Mar. 31, 2019
Sep. 30, 2018
Mar. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Fair Value- Net PP&E (held for sale) $ 194   $ 166      
Before-Tax Loss - Net PP&E (held for sale) 351   28      
Fair Value - Cost and Equity Method Investments   $ 30   $ 171 $ 201 $ 250
Before-Tax Loss - Cost and Equity method investments   95   60 43 44
Fair Value, Inputs, Level 1 [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Fair Value- Net PP&E (held for sale) 194   166      
Fair Value - Cost and Equity Method Investments   0   171 201 0
Fair Value, Inputs, Level 2 [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Fair Value- Net PP&E (held for sale) 0   0      
Fair Value - Cost and Equity Method Investments   30   0 0 0
Fair Value, Inputs, Level 3 [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Fair Value- Net PP&E (held for sale) $ 0   $ 0      
Fair Value - Cost and Equity Method Investments   $ 0   $ 0 $ 0 $ 250