CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
OPERATING REVENUE
Total operating revenue	$ 1,724	$ 1,799	$ 3,516	$ 3,717
OPERATING EXPENSES
Cost of services and products (exclusive of depreciation and amortization)	440	490	879	963
Selling, general and administrative	106	139	213	282
Operating expenses—affiliates	190	164	384	359
Depreciation and amortization	231	327	548	655
Total operating expenses	967	1,120	2,024	2,259
OPERATING INCOME	757	679	1,492	1,458
OTHER (EXPENSE) INCOME
Interest expense	(47)	(75)	(95)	(150)
Interest expense—affiliate, net	(31)	(16)	(62)	(32)
Other income (expense), net	2	(5)	(4)	(13)
Total other expense, net	(76)	(96)	(161)	(195)
INCOME BEFORE INCOME TAX EXPENSE	681	583	1,331	1,263
Income tax expense	172	153	340	330
NET INCOME	509	430	991	933
Non-affiliate services
OPERATING REVENUE
Total operating revenue	1,147	1,207	2,317	2,442
Affiliate Services [Member]
OPERATING REVENUE
Total operating revenue	$ 577	$ 592	$ 1,199	$ 1,275