Preferred Stock Other Disclosures (Details) (USD $)	12 Months Ended	0 Months Ended
	Dec. 31, 2014	Oct. 01, 2007	Apr. 07, 2010	Jul. 31, 2011
Floating Rate Non-Cumulative Preferred Stock, Series F ($25 stated value) [Member]
Class of Stock [Line Items]
Dividend Rate	3.549%
Redemption price per share (usd per share)			$ 25
14,950,000 Depositary Shares each representing a one-fortieth interest in a share of Floating Rate Non-Cumulative Preferred Stock, Series G ($1,000 stated value) [Member]
Class of Stock [Line Items]
Basis spread on variable rate	0.75%
Dividend Rate	4.056%
Redemption price per share (usd per share)	1,000
14,950,000 Depositary Shares each representing a one-fortieth interest in a share of 6.50% Non-Cumulative Preferred Stock, Series H ($1,000 stated value) [Member]
Class of Stock [Line Items]
Dividend Rate	6.50%
Redemption price per share (usd per share)				$ 1,000
6,000,000 Depositary shares each representing a one-fourth interest in a share of Adjustable Rate Cumulative Preferred Stock, Series D ($100 stated value) [Member]
Class of Stock [Line Items]
Dividend Rate	4.50%
Redemption price per share (usd per share)	100
Redemption price per depositary share (usd per share)	25
$2.8575 Cumulative Preferred Stock ($50 stated value) [Member]
Class of Stock [Line Items]
Dividend Rate	5.715%
Dividend per share (usd per share)	2.8575	$ 2.8575
Redemption price per share (usd per share)		$ 50
Minimum [Member] | Floating Rate Non-Cumulative Preferred Stock, Series F ($25 stated value) [Member]
Class of Stock [Line Items]
Dividend Rate	3.50%
Minimum [Member] | 14,950,000 Depositary Shares each representing a one-fortieth interest in a share of Floating Rate Non-Cumulative Preferred Stock, Series G ($1,000 stated value) [Member]
Class of Stock [Line Items]
Dividend Rate	4.00%
Minimum [Member] | 6,000,000 Depositary shares each representing a one-fourth interest in a share of Adjustable Rate Cumulative Preferred Stock, Series D ($100 stated value) [Member]
Class of Stock [Line Items]
Dividend Rate	4.50%
Maximum [Member] | 6,000,000 Depositary shares each representing a one-fourth interest in a share of Adjustable Rate Cumulative Preferred Stock, Series D ($100 stated value) [Member]
Class of Stock [Line Items]
Dividend Rate	10.50%
London Interbank Offered Rate (LIBOR) [Member] | Floating Rate Non-Cumulative Preferred Stock, Series F ($25 stated value) [Member]
Class of Stock [Line Items]
Basis spread on variable rate	0.75%