Debt - Summary of outstanding debt (Details)	Dec. 31, 2020 USD ($)	Dec. 31, 2020 EUR (€)	May 12, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Nov. 15, 2019 USD ($)	May 02, 2019 USD ($)
Debt Instrument [Line Items]
Total debt	$ 7,729,000,000				$ 7,339,000,000
Less: Short-term debt and current portion of long-term debt	448,000,000				712,000,000
Long-term debt	7,281,000,000				6,627,000,000
Other
Debt Instrument [Line Items]
Total debt	48,000,000				1,000,000
Five Point Zero Zero Percent Senior Notes Due Twenty Twenty [Member] | Senior Notes
Debt Instrument [Line Items]
Total debt	$ 0				600,000,000
Interest rate on debt	5.00%	5.00%
2.80% Senior Notes due March 2021 | Senior Notes
Debt Instrument [Line Items]
Total debt	$ 400,000,000				399,000,000
Interest rate on debt	2.80%	2.80%		2.80%
Debt face value				$ 400,000,000
2.20% Senior Notes due November 2022 | Senior Notes
Debt Instrument [Line Items]
Total debt	$ 498,000,000				497,000,000
Interest rate on debt	2.20%	2.20%				2.20%
Debt face value						$ 500,000,000
4.00% Senior Notes due November 2023 | Senior Notes
Debt Instrument [Line Items]
Total debt	$ 349,000,000				348,000,000
Interest rate on debt	4.00%	4.00%
3.50% Senior Notes due June 2024 | Senior Notes
Debt Instrument [Line Items]
Total debt	$ 597,000,000				597,000,000
Interest rate on debt	3.50%	3.50%
3.875% Senior Notes due December 2025 | Senior Notes
Debt Instrument [Line Items]
Total debt	$ 747,000,000				746,000,000
Interest rate on debt	3.875%	3.875%
2.875% Senior Notes due May 2026 (EUR 500M) | Senior Notes
Debt Instrument [Line Items]
Total debt	$ 606,000,000				550,000,000
Interest rate on debt	2.875%	2.875%
Debt face value | €		€ 500,000,000
8.205% Junior Subordinated Notes due January 2027 | Senior Notes
Debt Instrument [Line Items]
Total debt	$ 521,000,000				521,000,000
Interest rate on debt	8.205%	8.205%
4.50% Senior Notes due December 2028 | Senior Notes
Debt Instrument [Line Items]
Total debt	$ 347,000,000				346,000,000
Interest rate on debt	4.50%	4.50%
3.75% Senior Notes due May 2029 | Senior Notes
Debt Instrument [Line Items]
Total debt	$ 744,000,000				744,000,000
Interest rate on debt	3.75%	3.75%					3.75%
Debt face value							$ 750,000,000
2.80% Senior Notes due May 2030 | Senior Notes
Debt Instrument [Line Items]
Total debt	$ 992,000,000				0
Interest rate on debt	2.80%	2.80%	2.80%
Debt face value			$ 1,000,000,000
6.25% Senior Notes due September 2040 | Senior Notes
Debt Instrument [Line Items]
Total debt	$ 296,000,000				296,000,000
Interest rate on debt	6.25%	6.25%
4.25% Senior Notes due December 2042 | Senior Notes
Debt Instrument [Line Items]
Total debt	$ 200,000,000				199,000,000
Interest rate on debt	4.25%	4.25%
4.45% Senior Notes due May 2043 | Senior Notes
Debt Instrument [Line Items]
Total debt	$ 247,000,000				246,000,000
Interest rate on debt	4.45%	4.45%
4.60% Senior Notes due June 2044 | Senior Notes
Debt Instrument [Line Items]
Total debt	$ 544,000,000				544,000,000
Interest rate on debt	4.60%	4.60%
4.75% Senior Notes due May 2045 | Senior Notes
Debt Instrument [Line Items]
Total debt	$ 593,000,000				593,000,000
Interest rate on debt	4.75%	4.75%
Commercial paper
Debt Instrument [Line Items]
Total debt	$ 0				$ 112,000,000