Income Taxes (Schedule of Components of Income Tax Expense (Benefit)) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Current income tax (benefit) expense, U.S. federal									$ 0	$ (2)	$ (12)
Current income tax (benefit) expense, Foreign									6	4	5
Current income tax (benefit) expense, State and local									80	65	35
Current Income Tax Expense									86	67	28
Deferred income tax expense (benefit), U.S. federal									280	178	328
Deferred income tax expense (benefit), Foreign									1	2	0
Deferred income tax expense (benefit), State and local									(39)	(1)	3
Deferred Income Tax Expense									242	179	331
Income tax expense from continuing operations	$ 169	$ 156	$ 95	$ (92)	$ 106	$ 119	$ (90)	$ 111	$ 328	$ 246	$ 359