Income Taxes (Details 1) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Currently payable
Federal income taxes	$ 912	$ 592	$ 394
Foreign income taxes	15	18	11
Total federal and foreign income taxes currently payable	927	610	405
Change in deferred federal and foreign income taxes	60	387	57
Total federal and foreign income taxes	$ 987	$ 997	$ 462