Income Taxes (Schedule of Earnings Before Income Taxes and Provision for Income Taxes) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
United States	$ 7,763	$ 6,929	$ 6,461
Outside United States	11	13	16
Earnings (loss) before income taxes	7,774	6,942	6,477
Current:
Federal - Current	2,350	2,066	2,870
State and local - Current	480	423	348
Outside United States - Current	3	4	5
Total current provision for income taxes	2,833	2,493	3,223
Deferred:
Federal - Deferred	(124)	(77)	(920)
State and local - Deferred	(5)	(9)	(9)
Total deferred provision for income taxes	(129)	(86)	(929)
Total provision for income taxes	$ 2,704	$ 2,407	$ 2,294