Related Party Transactions (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Significant transactions with related parties
Operating revenues and other income	$ 22	$ 21	$ 63	$ 59
Purchases	1	0	5	0
Operating expenses and selling, general and administrative expenses	45	16	135	43
Net interest (income) expense	$ 0	$ (1)	$ (2)	$ (5)