Revenue - Contract Balances with Customers (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Contract Asset	$ 117	$ 75
Contract with Customer, Asset, Reclassified to Receivable	42
Increase (Decrease) in Accounts Receivable	44	(201)	$ 1
Contract Liability	0	1
Contract with Customer, Liability, Revenue Recognized	(1)
Long-term Contract with Customer [Member]
Accounts receivable from contracts with customers	366	$ 348
Increase (Decrease) in Accounts Receivable	$ 18