Derivative and Hedging Instruments - Narrative (Details) € in Millions, $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2015 EUR (€)
Foreign Exchange Risk Management
Notional amount designated	$ 148			$ 148		$ 1,016
Unrealized gain (loss) on net investment hedges, before tax	48	$ 0		60	$ 0
Euro-Denominated Debt
Foreign Exchange Risk Management
Unrealized gain (loss) on net investment hedges, before tax	42			102
Cash Flow Hedging | Interest Rate Risk
Foreign Exchange Risk Management
Gain (loss) for contracts to purchase and sell foreign currency			$ (136)
Unrealized gain (loss) on cash flow hedges, net of tax				(130)
Estimated amount to be reclassified into interest expense within next 12 months				$ 4
Terms of the foreign currency forward contracts and foreign currency option contracts, less than				18 months
Net Investment Hedging | Euro-Denominated Debt
Foreign Exchange Risk Management
Notional amount designated | €							€ 1,650
Net foreign currency transaction pre-tax loss in AOCI	$ 49			$ 49