Summary of Significant Accounting Policies - Recently Adopted Accounting Standards (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Income tax provision		$ 2,629	$ 1,161	$ 1,670
Cumulative Effect, Period of Adoption, Adjustment | Accounting Standards Update, Number 2014-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Income tax provision	$ 55