Stockholders' Equity (Schedule of Components of Other Comprehensive Income (Loss), Net) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		161 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021
Stockholders' Equity Note [Abstract]
Foreign currency translation gain (loss), gross amount	$ 6	$ (10)	$ 9	$ 0
Foreign currency translation gain (loss), income tax (provision) benefit	1	4	(6)	(8)
Foreign currency translation gain (loss), net	7	(6)	3	(8)
Gain (loss) on cash flow hedges, gross amount	(4)	1	40	(50)
Gain (loss) on cash flow hedges, income tax (provision) benefit	1	0	(9)	12
Gain (loss) on cash flow hedges, net	(3)	1	31	(38)
Other Comprehensive Income (Loss), before Tax	2	(9)	45	(50)
Income tax (provision) benefit	2	4	(15)	4
Total other comprehensive income (loss), net of tax	4	(5)	30	(46)
Pension and postretirement benefits gain (loss), gross amount			(4)	0
Pension and postretirement benefits gain (loss), income tax (provision) benefit			0	0
Pension and postretirement benefits gain (loss), net	0	0	(4)	0
Other Comprehensive Income (Loss), before Tax	2	(9)	45	(50)
Income tax (provision) benefit	2	4	(15)	4
Total other comprehensive income (loss), net of tax	$ 4	$ (5)	30	(46)
Aggregate Board of Directors repurchase authorizations (in $ millions)			$ 0	$ 0	$ 5,866