Income Taxes (Schedule of Earnings Before Income Taxes and Provision for Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
United States	$ 21,867	$ 8,078	$ 7,763
Outside United States	(15)	0	11
Earnings before income taxes	21,852	8,078	7,774
Current:
Federal	4,093	2,516	2,350
State and local	390	451	480
Outside United States	6	0	3
Total current provision for income taxes	4,489	2,967	2,833
Deferred:
Federal	3,102	(140)	(124)
State and local	20	8	(5)
Outside United States	(3)	0	0
Total deferred provision for income taxes	3,119	(132)	(129)
Total provision for income taxes	$ 7,608	$ 2,835	$ 2,704