Goodwill and Other Intangible Assets (Identifiable Intangible Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Acquired Finite Lived Intangible Assets
Gross carrying amount	$ 2,067	$ 1,781
Accumulated amortization	(1,381)	(1,276)
Net carrying amount	686	505
CDI [Member]
Acquired Finite Lived Intangible Assets
Gross carrying amount	903	693
Accumulated amortization	(634)	(585)
Net carrying amount	$ 269	108
Weighted-average remaining life	8 years 5 months
Other, primarily customer relationship intangibles [Member]
Acquired Finite Lived Intangible Assets
Gross carrying amount	$ 1,164	1,088
Accumulated amortization	(747)	(691)
Net carrying amount	$ 417	$ 397
Weighted-average remaining life	14 years