Consolidated Statements of Comprehensive Income Consolidated Statement of Comprehensive Income - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Statement of Comprehensive Income [Abstract]
Net Income (Loss) Attributable to Parent		$ 468	$ 447
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax		2	279
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax		(42)	150
Other Comprehensive Income (Loss), Brokered Time Deposits, Net of Tax		0	0
Other Comprehensive Income (Loss), Long Term Debt, Adjustment, Net of Tax	[1]	(1)	(2)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax		(5)	59
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent		(46)	486
Comprehensive Income (Loss), Net of Tax, Attributable to Parent		$ 422	$ 933

[1] Related to the Company's early adoption of the ASU 2016-01 provision related to changes in instrument-specific credit risk. See Note 1, "Significant Accounting Policies," and Note 18, "Accumulated Other Comprehensive (Loss)/Income," for additional information.