Income Taxes Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income tax benefit (expense) at U.S. statutory rate	$ 365	$ (47)	$ (653)
Valuation allowance	(63)	(4)	529
Non-controlling interest	(4)	26	(6)
Goodwill impairment	0	(18)	0
Stock dispositions	0	69	0
Income not subject to taxation	(314)	14	220
Enactment of U.S. tax legislation, net of valuation allowance	0	0	392
Other	(4)	(26)	50
Income tax (expense) benefit	$ (20)	$ 14	$ 532