Income Taxes - Reconciliation of Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes [Line Items]
Federal statutory tax rate		21.00%	21.00%	35.00%
Reconciliation of Statutory to Effective Tax (Benefit) Expense
U.S. federal income tax expense at the statutory rate of 21% (35% for 2017)		$ 37	$ 212	$ 307
Federal and state tax on accelerated royalty income transaction		334	0	0
Net establishment (release) of valuation allowances	$ 88
Net foreign losses (income) with no tax due to valuation allowances		48	7	(7)
U.S. charges (benefits) related to foreign tax credits, R&D and foreign derived intangible deduction		(17)	20	(23)
Adjustment for foreign income taxed at different rates		16	30	(55)
Net establishment (resolution) of uncertain tax positions		7	18	(6)
Deferred tax impact of enacted tax rate and law changes		3	0	389
State income taxes, net of U.S. federal benefit		(1)	(1)	9
Provision for undistributed foreign earnings, net		0	(9)	(162)
Transition tax		0	8	77
Domestic production activities deduction		0	(1)	(16)
Other		5	(1)	(6)
United States and Foreign Tax (Benefit) Expense		474	303	513
Foreign Tax Authority
Reconciliation of Statutory to Effective Tax (Benefit) Expense
Net establishment (release) of valuation allowances		140	(5)	1
Domestic Tax Authority
Reconciliation of Statutory to Effective Tax (Benefit) Expense
Net establishment (release) of valuation allowances		$ (98)	$ 25	$ 5