Securities (Details 3) $ in Millions	Jun. 30, 2016 USD ($)
Securities available for sale
One Year or Less	$ 6
Over One Year Through Five Years	380
Over Five Years Through Ten Years	3,205
Over Ten Years	9,248
Total Fair Value	12,839
U.S. Treasury
Securities available for sale
One Year or Less	0
Over One Year Through Five Years	0
Over Five Years Through Ten Years	159
Over Ten Years	0
Total Fair Value	159
Residential mortgage-backed securities, U.S. government agency and government-sponsored agencies
Securities available for sale
One Year or Less	0
Over One Year Through Five Years	14
Over Five Years Through Ten Years	351
Over Ten Years	5,687
Total Fair Value	6,052
Residential mortgage-backed securities, Privately issued
Securities available for sale
One Year or Less	0
Over One Year Through Five Years	3
Over Five Years Through Ten Years	0
Over Ten Years	245
Total Fair Value	248
Privately issued - commercial mortgage-backed securities
Securities available for sale
One Year or Less	0
Over One Year Through Five Years	0
Over Five Years Through Ten Years	37
Over Ten Years	1,490
Total Fair Value	1,527
Collateralized loan obligations
Securities available for sale
One Year or Less	0
Over One Year Through Five Years	16
Over Five Years Through Ten Years	1,883
Over Ten Years	1,339
Total Fair Value	3,238
Other Asset Liability Management Securities
Securities available for sale
One Year or Less	0
Over One Year Through Five Years	2
Over Five Years Through Ten Years	5
Over Ten Years	0
Total Fair Value	7
Asset Liability Management securities
Securities available for sale
One Year or Less	0
Over One Year Through Five Years	35
Over Five Years Through Ten Years	2,435
Over Ten Years	8,761
Total Fair Value	11,231
Other debt securities, Direct bank purchase bonds
Securities available for sale
One Year or Less	6
Over One Year Through Five Years	344
Over Five Years Through Ten Years	770
Over Ten Years	455
Total Fair Value	1,575
Other debt securities, Other
Securities available for sale
One Year or Less	0
Over One Year Through Five Years	1
Over Five Years Through Ten Years	0
Over Ten Years	32
Total Fair Value	$ 33