Background and Summary of Significant Accounting Policies - Recently Adopted Accounting Pronouncements (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Jan. 01, 2020	Dec. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of new accounting principle in period of adoption, net of tax	$ 13,554	$ 11,635	$ 10,098
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of new accounting principle in period of adoption, net of tax	$ 3,504	1,585	48		$ 67
Retained Earnings | Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of new accounting principle in period of adoption, net of tax		$ 0	$ 0	$ 3	$ 3