Loan Servicing (Residential MSRs Sensitivity) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013 Yr	Dec. 31, 2012 Yr
Residential Mortgage Servicing Rights [Member]
Weighted average prepayment speed	6.90%	17.30%
Effect on fair value of a 10% increase in weighted average prepayment speed	$ (33)	$ (35)
Effect on fair value of a 20% increase in weighted average prepayment speed	(64)	(67)
Weighted average OAS	9.30%	8.30%
Effect on fair value of a 10% increase in weighted average OAS	(39)	(17)
Effect on fair value of a 20% increase in weighted average OAS	$ (75)	$ (33)
Composition of residential mortgage loans serviced for others	100.00%	100.00%
Weighted average life, in years	7.9	4.4
Residential Mortgage Servicing Rights [Member] | Maximum [Member]
Weighted average prepayment speed	8.00%	18.50%
Weighted average OAS	9.90%	8.40%
Residential Mortgage Servicing Rights [Member] | Minimum [Member]
Weighted average prepayment speed	5.50%	15.30%
Weighted average OAS	9.10%	8.20%
Fixed-Rate Residential Mortgage [Member]
Composition of residential mortgage loans serviced for others	99.70%	99.40%
Adjustable Rate Residential Mortgage [Member]
Composition of residential mortgage loans serviced for others	0.30%	0.60%