Income Taxes (Schedule of Earnings Before Income Taxes and Provision for Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
United States	$ 6,842	$ 266	$ 9,441
Outside United States	48	500	(100)
Earnings before income taxes	6,890	766	9,341
Current:
Federal	2,025	1,686	1,911
State and local	553	470	519
Outside United States	22	3	1
Total current provision for income taxes	2,600	2,159	2,431
Deferred:
Federal	(130)	(78)	(18)
State and local	(34)	(19)	(42)
Outside United States	0	2	3
Total deferred provision for income taxes	(164)	(95)	(57)	$ (57)
Total provision for income taxes	$ 2,436	$ 2,064	$ 2,374