Other Changes and Developments (Details) (Preferred Stock Including Additional Paid in Capital, USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 13, 2012	Mar. 31, 2013
Other Business Events Disclousre
Stock Issued During Period, Value, New Issues	$ 0	$ 900
Non-Cumulative Preferred Stock, Series P
Other Business Events Disclousre
Stock Issued During Period, Value, New Issues		900
Subsequent Event | Fixed-to-Floating Rate Non-Cumulative Preferred Stock, Series Q [Member]
Other Business Events Disclousre
Stock Issued During Period, Value, New Issues		$ 1,481