Income Taxes (Breakdown of provision for income taxes) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Current expense:
Federal	$ 1,004	$ 273	$ 83
State	100	70	26
Foreign	3	2	2
Total current expense	1,107	345	111
Deferred expense:
Federal	256	396	163
State	32	23	22
Total deferred expense	288	419	185
Income Tax Expense
Provision for income taxes	$ 1,395	$ 764	$ 296