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		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Derivative [Line Items]
Amount of gain (loss) recognized in AOCI	$ (32)	$ 10	$ 141	$ 44
Amount of gain (loss) recognized in income on derivative (amount excluded from effectiveness testing)	11	10	23	17
Sterling Notes
Derivative [Line Items]
Amount of gain (loss) recognized in AOCI	3	16	33	(1)
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	(33)	(6)	104	46
Amount of gain (loss) recognized in income on derivative (amount excluded from effectiveness testing)	11	10	23	17
Foreign exchange
Derivative [Line Items]
Amount of gain (loss) recognized in AOCI			4	(1)
Amount of gain (loss) recognized in income on derivative (amount excluded from effectiveness testing)			$ 0	$ 0
Foreign exchange | Other (expense) income, net
Derivative [Line Items]
Amount of gain (loss) recognized in AOCI	(2)	0
Amount of gain (loss) recognized in income on derivative (amount excluded from effectiveness testing)	$ 0	$ 0