Schedule I - Condensed Financial Information of Parent (Statement of Comprehensive Income Parenthetical) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Foreign currency translation adjustments, income tax benefit (expense)	$ 1	$ 2	$ 17
Foreign currency, reclassification to earnings, income tax benefit (expense)	0	0	0
Change in derivative fair value, income tax benefit (expense)	(74)	(27)	(10)
Derivative reclassification to earnings, income tax benefit (expense)	12	24	1
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Tax	0	(1)	1
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, Tax	(10)	(1)	(6)
Pension, amortization of net actuarial loss, income tax benefit (expense)	13	2	135
Parent Company
Condensed Financial Statements, Captions [Line Items]
Foreign currency translation adjustments, income tax benefit (expense)	1	2	11
Foreign currency, reclassification to earnings, income tax benefit (expense)	0	0	0
Change in derivative fair value, income tax benefit (expense)	53	16	13
Derivative reclassification to earnings, income tax benefit (expense)	(4)	(13)	1
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Tax	0	(1)	(1)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, Tax	6	(1)	6
Pension, amortization of net actuarial loss, income tax benefit (expense)	$ (13)	$ (2)	$ (126)