Derivative Financial Instruments (Schedule of Comprehensive Income (Loss) Impact of Items Designated as Net Investment Hedges) (Details) - Designated as Hedging Instrument - Net investment hedges - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Derivative [Line Items]
Amount of gain (loss) recognized in AOCI	$ (102)	$ 101	$ 39	$ 145
Amount of gain (loss) recognized in income on derivative (amount excluded from effectiveness testing)	10	16	33	33
Sterling Notes
Derivative [Line Items]
Amount of gain (loss) recognized in AOCI	(23)	16	10	15
Amount of gain (loss) recognized in income on derivative (amount excluded from effectiveness testing)	0	0	0	0
Cross-currency swaps | Interest expense, net
Derivative [Line Items]
Amount of gain (loss) recognized in AOCI	(78)	82	26	128
Amount of gain (loss) recognized in income on derivative (amount excluded from effectiveness testing)	10	16	33	33
Foreign exchange
Derivative [Line Items]
Amount of gain (loss) recognized in AOCI			3	2
Amount of gain (loss) recognized in income on derivative (amount excluded from effectiveness testing)			$ 0	$ 0
Foreign exchange | Other expense, net
Derivative [Line Items]
Amount of gain (loss) recognized in AOCI	(1)	3
Amount of gain (loss) recognized in income on derivative (amount excluded from effectiveness testing)	$ 0	$ 0