Income Taxes - Narrative (Details) € in Millions, $ in Millions	1 Months Ended			3 Months Ended			6 Months Ended	12 Months Ended
	Jan. 31, 2020 USD ($)	Jan. 31, 2020 EUR (€)	Oct. 31, 2018 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Jun. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2017 EUR (€)
Income Tax [Line Items]
Federal income tax provision at statutory rate								21.00%	21.00%	21.00%
Tax benefit								$ (419)	$ (130)	$ (29)
Valuation allowance				$ 181				228	181
Reduction in unrecognized tax benefits resulting from Closing Agreement								3	163	312
Additional federal and state cash payments related to Closing Agreement							$ 345
Additional tax expense (benefit) for effects of U.S. Tax Reform Act					$ (340)
NOL carryforwards, foreign								46
Deferred tax assets, intangible assets				1,289				1,287	1,289
Deferred tax liabilities, intangible assets				142				147	142
Unrecognized tax benefits				1,037	926		926	1,166	1,037	926	$ 1,138
Unrecognized tax benefits that would affect effective tax rate								706
Accrued interest and penalties related to uncertain tax positions				72	$ 87		$ 87	93	72	87
Interest expense related to uncertain tax positions								19	14	$ 11
State
Income Tax [Line Items]
Tax credit carryforward								227
R&D Credit
Income Tax [Line Items]
Valuation allowance				71				107	71
US IP Onshoring
Income Tax [Line Items]
Additional federal and state cash payments related to Closing Agreement			$ 334
French Tax Authority
Income Tax [Line Items]
Tax expense (benefit) related to tax settlement									54
Total assessment, including penalties and interest, not recorded											$ 638	€ 571
Tax payments, including interest and penalties	$ 179	€ 161
Settlement From Closing Agreement
Income Tax [Line Items]
Tax expense (benefit) related to tax settlement						$ 70
Reduction in unrecognized tax benefits resulting from Closing Agreement						437
Indirect Tax Benefits Due to Closing Agreement
Income Tax [Line Items]
Tax expense (benefit) related to tax settlement						$ (185)
UK IP Onshoring
Income Tax [Line Items]
Tax benefit				230
Net Deferred tax asset related to the amortizable tax basis in transferred intellectual property				1,100					1,100
Deferred tax liabilities, domestic tax on foreign earnings				920					920
Valuation allowance				$ 110					$ 110
Deferred tax assets, intangible assets								1,100
UK IP Onshoring | Minimum
Income Tax [Line Items]
Amortizable tax basis, recovery period									3 years
UK IP Onshoring | Maximum
Income Tax [Line Items]
Amortizable tax basis, recovery period									25 years
U.S.
Income Tax [Line Items]
Deferred tax liabilities, intangible assets								881
US IP Onshoring
Income Tax [Line Items]
Tax benefit								$ 31