Financial Instruments - Narrative (Details) € in Billions	3 Months Ended	9 Months Ended
	Sep. 30, 2021 USD ($)	Sep. 30, 2021 USD ($) contract	Sep. 30, 2021 EUR (€)	Sep. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Derivative [Line Items]
Different types of derivative, number | contract		3
Exchange rate movements reducing long-term debt during period		$ 42,000,000
Notional value				$ 6,416,000,000	$ 9,831,000,000
Interest rate			0.375%	0.375%
Net Investment Hedging
Derivative [Line Items]
Exchange rate movements reducing long-term debt since inception	$ 1,000,000	57,000,000
Derivatives Designated as Hedging Instruments:
Derivative [Line Items]
Notional value				$ 1,595,000,000	2,278,000,000
Interest Rate Swap | Derivatives Designated as Hedging Instruments:
Derivative [Line Items]
Notional value				1,273,000,000	1,923,000,000
Interest Rate Swap | Derivatives Designated as Hedging Instruments: | Fair Value Hedging
Derivative [Line Items]
Notional value					1,923,000,000
Line of Credit
Derivative [Line Items]
Intercompany Euro-denominated credit facility loan			€ 4.1	4,700,000,000
Line of Credit | Net Investment Hedging
Derivative [Line Items]
Exchange rate movements reducing long-term debt since inception		$ 57,000,000
2.20% Notes due 2022
Derivative [Line Items]
Face amount				$ 500,000,000	$ 500,000,000
Interest rate			2.20%	2.20%	2.20%