Income Taxes - Effective Tax Rate Reconciliation (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Federal income tax provision at statutory rate	$ 549	$ 343	$ 394
State taxes, net of federal benefit	49	20	36
Research and development credits	(70)	(38)	(46)
Foreign rate differential	(103)	(104)	(198)
Foreign-derived intangible income	(40)	(1)	0
Change in tax reserves	60	96	285
Audit settlements	0	54	(115)
Excess tax benefits related to share-based payments	(30)	(2)	(58)
U.S. Tax Reform Act	0	0	(340)
Change in valuation allowance	35	11	61
Intra-entity IP Transfer	(31)	(230)	0
Other	0	(19)	10
Income tax expense	$ 419	$ 130	$ 29
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Federal income tax provision at statutory rate	21.00%	21.00%	21.00%
State taxes, net of federal benefit	2.00%	1.00%	2.00%
Research and development credits	(3.00%)	(2.00%)	(2.00%)
Foreign rate differential	(4.00%)	(7.00%)	(11.00%)
Foreign-derived intangible income	(2.00%)	0.00%	0.00%
Change in tax reserves	2.00%	6.00%	15.00%
Audit settlements	0.00%	3.00%	(6.00%)
Excess tax benefits related to share-based payments	(1.00%)	0.00%	(3.00%)
U.S. Tax Reform Act	0	0	(0.18)
Change in valuation allowance	2.00%	1.00%	3.00%
Intra-entity IP Transfer	(1.00%)	(14.00%)	0.00%
Other	0.00%	(1.00%)	1.00%
Income tax expense	16.00%	8.00%	2.00%

This element represents the change attributable to effective income tax rate due to change in reserve.

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Effective Income Tax Rate Reconciliation, Deduction, Foreign-derived Intangible Income

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This element represents the portion of the difference between the total income tax expense (benefit) as reported in the Income Statement and the expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to the change in tax reserves.

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to changes in the valuation allowance for deferred tax assets.

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Percentage of difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying domestic federal statutory income tax rate to pretax income (loss) from continuing operations, attributable to disposition of asset. Includes, but is not limited to, intra-entity transfer of asset other than inventory.

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to statutory income tax expense (benefit) outside of the country of domicile.

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Amount of reported income tax expense (benefit) in excess of (less than) expected income tax expense (benefit) computed by applying domestic federal statutory income tax rate to pretax income (loss) from continuing operations, attributable to Tax Cuts and Jobs Act.

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to income tax settlements. Including, but not limited to, domestic tax settlement, foreign tax settlement, state and local tax settlement, and other tax settlements.

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to increase (decrease) in the valuation allowance for deferred tax assets.

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