Annual report pursuant to Section 13 and 15(d)

Schedule II - Valuation and Qualifying Accounts (Details)

v3.20.4
Schedule II - Valuation and Qualifying Accounts (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Allowance for doubtful accounts on accounts receivable and contract assets [Member]      
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]      
Balance at beginning of period $ 0 $ 30 $ 30
Charged to cost and expenses 7 16 0
Charged to other accounts 0 0 0
Deductions 0 (46) 0
Balance at end of period 7 0 30
Deferred tax asset valuation allowance [Member]      
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]      
Balance at beginning of period 196 686 806
Charged to cost and expenses (6) (490) (120)
Charged to other accounts 0 0 0
Deductions 0 0 0
Balance at end of period $ 190 $ 196 $ 686