Comprehensive (Loss) Income (Summary Of The Activity In Other Comprehensive Income (Loss), Net Of The Related Tax Effects) (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2021	Mar. 31, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at the beginning of period		$ (39)	$ 9
Other comprehensive (loss) income before reclassifications:
Pre-tax amount		32	(61)
Tax provision		(5)	12
After-tax amount		27	(49)
Amounts reclassified from accumulated other comprehensive (loss) income	[1]	(5)	(1)
Net current period other comprehensive income (loss)		22	(50)
Balance at the end of period		(17)	(41)
Unrealized Gains (Losses) On Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at the beginning of period		(16)	13
Other comprehensive (loss) income before reclassifications:
Pre-tax amount		34	(45)
Tax provision		(5)	12
After-tax amount		29	(34)
Amounts reclassified from accumulated other comprehensive (loss) income	[1]	(5)	(1)
Amount reclassified within accumulated other comprehensive (loss) income	[2]	(9)
Net current period other comprehensive income (loss)		14	(34)
Balance at the end of period		(2)	(21)
Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at the beginning of period		(23)	(5)
Other comprehensive (loss) income before reclassifications:
Pre-tax amount		(2)	(15)
After-tax amount		(2)	(15)
Amount reclassified within accumulated other comprehensive (loss) income	[2]	9
Net current period other comprehensive income (loss)		8	(15)
Balance at the end of period		$ (15)	$ (20)

[1] Amounts are net of tax. See reclassification out of accumulated other comprehensive income below for further details.

[2] Represents reclassifications from our net investment hedge related to foreign currency exchange rate fluctuations.