Debt - Summary of Long-term Debt (Details) $ in Millions	Sep. 30, 2020 USD ($)	Sep. 30, 2020 EUR (€)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 EUR (€)
Debt Instrument [Line Items]
Principal amount at par	$ 16,158		$ 14,873
Fair value	18,150		15,949
Senior Notes
Debt Instrument [Line Items]
Principal amount at par | €		€ 5,170,000,000
Senior Notes | 5.375% Senior Notes
Debt Instrument [Line Items]
Principal amount at par	500		500
Fair value	$ 507		$ 518
Interest rate	5.375%	5.375%	5.375%	5.375%
Senior Notes | 5.500% Senior Notes
Debt Instrument [Line Items]
Principal amount at par	$ 700		$ 700
Fair value	$ 736		$ 744
Interest rate	5.50%	5.50%	5.50%	5.50%
Senior Notes | 5.750% Senior Notes
Debt Instrument [Line Items]
Principal amount at par	$ 400		$ 400
Fair value	$ 445		$ 444
Interest rate	5.75%	5.75%	5.75%	5.75%
Senior Notes | 5.875% Senior Notes
Debt Instrument [Line Items]
Principal amount at par	$ 800		$ 800
Fair value	$ 906		$ 896
Interest rate	5.875%	5.875%	5.875%	5.875%
Senior Notes | 3.000% Senior Notes
Debt Instrument [Line Items]
Principal amount at par	$ 551	€ 470,000,000	$ 0	€ 470,000,000
Fair value	$ 575		$ 0
Interest rate	3.00%	3.00%	3.00%	3.00%
Senior Notes | 3.625% Senior Notes
Debt Instrument [Line Items]
Principal amount at par	$ 500		$ 0
Fair value	$ 523		$ 0
Interest rate	3.625%	3.625%	3.625%	3.625%
Senior Notes | 4.375% Senior Notes
Debt Instrument [Line Items]
Principal amount at par	$ 1,000		$ 1,000
Fair value	$ 1,092		$ 1,026
Interest rate	4.375%	4.375%	4.375%	4.375%
Senior Notes | 3.625% Senior Notes
Debt Instrument [Line Items]
Principal amount at par	$ 1,523	€ 1,300,000,000	$ 1,459	€ 1,300,000,000
Fair value	$ 1,651		$ 1,565
Interest rate	3.625%	3.625%	3.625%	3.625%
Senior Notes | 4.875% Senior Notes
Debt Instrument [Line Items]
Principal amount at par	$ 1,600		$ 1,600
Fair value	$ 1,800		$ 1,670
Interest rate	4.875%	4.875%	4.875%	4.875%
Senior Notes | 5.875% Senior Notes
Debt Instrument [Line Items]
Principal amount at par	$ 1,900		$ 1,900
Fair value	$ 2,269		$ 2,111
Interest rate	5.875%	5.875%	5.875%	5.875%
Senior Notes | 4.625% Senior Notes
Debt Instrument [Line Items]
Principal amount at par	$ 1,289	€ 1,100,000,000	$ 1,234	€ 1,100,000,000
Fair value	$ 1,495		$ 1,378
Interest rate	4.625%	4.625%	4.625%	4.625%
Senior Notes | 6.375% Senior Notes
Debt Instrument [Line Items]
Principal amount at par	$ 800		$ 800
Fair value	$ 989		$ 916
Interest rate	6.375%	6.375%	6.375%	6.375%
Senior Notes | 3.875% Senior Notes
Debt Instrument [Line Items]
Principal amount at par	$ 1,406	€ 1,200,000,000	$ 1,346	€ 1,200,000,000
Fair value	$ 1,556		$ 1,429
Interest rate	3.875%	3.875%	3.875%	3.875%
Senior Notes | 5.375% Senior Notes
Debt Instrument [Line Items]
Principal amount at par	$ 900		$ 900
Fair value	$ 1,062		$ 960
Interest rate	5.375%	5.375%	5.375%	5.375%
Senior Notes | 3.625% Senior Notes
Debt Instrument [Line Items]
Principal amount at par	$ 1,289	€ 1,100,000,000	$ 1,234	€ 1,100,000,000
Fair value	$ 1,402		$ 1,273
Interest rate	3.625%	3.625%	3.625%	3.625%
Senior Notes | 4.875% Senior Notes
Debt Instrument [Line Items]
Principal amount at par	$ 1,000		$ 1,000
Fair value	$ 1,142		$ 1,019
Interest rate	4.875%	4.875%	4.875%	4.875%