Federal and Foreign Income Tax (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Income tax expense and taxes paid [Abstract]
Current tax, United States									$ 260	$ 436	$ 532
Current Tax, Foreign									236	242	161
Deferred tax, principally United States									25	136	86
Federal and Foreign Income Tax	150	68	127	176	234	212	184	184	521	814	779
Federal and foreign income taxes paid									$ 598	$ 500	$ 720