Derivative Instruments - Balance Sheet Classification (Details) € in Millions, $ in Millions	Mar. 31, 2021 USD ($)	Mar. 31, 2021 EUR (€)	Dec. 31, 2020 USD ($)	Dec. 31, 2020 EUR (€)	Mar. 31, 2020 USD ($)	Mar. 31, 2020 EUR (€)
Derivatives, Fair Value
Total asset derivatives	$ 28		$ 25		$ 92
Total liability derivatives	109		170		11
Current derivative asset	18		13		30
Current derivative liability	9		15		6
Noncurrent derivative asset	10		12		62
Noncurrent derivative liability	100		155		5
Derivatives designated as hedging instruments
Derivatives, Fair Value
Total asset derivatives	23		24		82
Total liability derivatives	106		167		6
Derivatives designated as hedging instruments | Interest rate swaps - fair value hedges
Derivatives, Fair Value
Notional amount | €		€ 725		€ 725		€ 725
Total asset derivatives	13		17		11
Derivatives designated as hedging instruments | Cash flow hedges of foreign exchange risk
Derivatives, Fair Value
Notional amount	978		978		1,424
Total asset derivatives	8		6		66
Total liability derivatives	67		115		4
Derivatives designated as hedging instruments | Interest rate swaps - cash flow hedges
Derivatives, Fair Value
Notional amount	0		0		105
Total liability derivatives					2
Derivatives designated as hedging instruments | Net investment hedges
Derivatives, Fair Value
Notional amount | €		€ 311		€ 311		€ 160
Total asset derivatives	2		1		5
Total liability derivatives	39		52
Derivatives not designated as hedging instruments | Foreign exchange derivative contracts
Derivatives, Fair Value
Notional amount	301		247		306
Total asset derivatives	5		1		10
Total liability derivatives	$ 3		$ 3		$ 5