Revenues - Receivables (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Receivables for Product and Services in Accounts Receivable, Net	$ 758	$ 792
Contract Liabilities	43	37
Contract with Customer, Liability, Revenue Recognized	18
Accounts Receivable, Net of Allowance for Credit Losses of $32 at March 31, 2021 and $32 at December 31, 2020	$ 793	$ 826