Income Taxes - Tax Carryforwards and Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Operating Loss and Tax Credit Carryforwards [Line Items]
Net operating loss carryforwards	$ 330	$ 299
Tax credit carryforwards	4,646	$ 3,859
Federal [Member]
Operating Loss and Tax Credit Carryforwards [Line Items]
Net operating loss carryforwards	51
Tax credit carryforwards	4,296
Net operating loss carryforwards with indefinite expiration period	49
State [Member]
Operating Loss and Tax Credit Carryforwards [Line Items]
Net operating loss carryforwards	264
Tax credit carryforwards	345
Tax credit carryforward with indefinite expiration period	191
Foreign [Member]
Operating Loss and Tax Credit Carryforwards [Line Items]
Net operating loss carryforwards	15
Tax credit carryforwards	$ 5