Fair Value of Financial Instruments - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Footnote Information) (Details) - Measured on a recurring basis - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	$ 28,249	$ 31,956
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	$ 269	$ 192