Income Taxes (Schedule of Reconciliation between the Statutory Federal Income Tax Rate and the Effective Tax Rate) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Differences between the statutory federal income tax rate and the effective tax rate
Benefit for income taxes at statutory federal rate, Amount	$ (90)	$ (150)	$ (991)
State income taxes, net of federal income tax benefit, Amount	(104)	(114)	(10)
Net income attributable to noncontrolling interests, Amount	(18)	(18)	(22)
Change in valuation allowance, Amount	340	212	26
Change in uncertain tax position, Amount		9
Federal rate change, Amount			32
Federal and state tax credits, Amount		(17)	(5)
Nondeductible goodwill, Amount	11	30	504
Nondeductible settlments, Amount		22
Nondeductible loss on divestiture, Amount	15
Other, Amount	6	15	17
Total provision for (benefit from) income taxes for loss from continuing operations	$ 160	$ (11)	$ (449)
Provision for income taxes at statutory federal rate, Percentage	21.00%	21.00%	35.00%
State income taxes, net of federal income tax benefit, Percentage	24.30%	16.00%	0.30%
Net income attributable to noncontrolling interests, Percentage	4.20%	2.50%	0.80%
Change in valuation allowance, Percentage	(79.20%)	(29.70%)	(0.90%)
Change in uncertain tax position, Percentage		(1.30%)
Federal rate change, Percentage			(1.10%)
Federal and state tax credits, Percentage		2.40%	0.10%
Nondeductible goodwill, Percentage	(2.60%)	(4.20%)	(17.80%)
Nondeductible settlements, Percentage		(3.10%)
Nondeductible loss on divestiture, Percentage	(3.50%)
Other, Percentage	(1.40%)	(2.10%)	(0.60%)
Benefit from income taxes from continuing operations, Percentage	(37.20%)	1.50%	15.80%