CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 209	$ 166
Other comprehensive income (loss):
Net unrealized derivative instrument gains (losses) arising during the periods, net of income taxes of $39 and $34, respectively	65	59
Reclassification adjustment for net derivative losses included in net income, net of income taxes of ($1) and $4, respectively	(2)	7
Net unrealized available for sale securities gains (losses) arising during the periods, net of income taxes of $54 and $41, respectively	90	71
Other-than-temporary impairment not recognized in earnings on securities, net of income taxes of ($11) and ($11), respectively	(19)	(19)
Reclassification of net securities gains to net income, net of income taxes of ($3) and ($7), respectively	(4)	(14)
Defined benefit pension plans:
Amortization of actuarial loss, net of income taxes $1 and $1, respectively	2	1
Total other comprehensive income, net of income taxes	132	105
Total comprehensive income	$ 341	$ 271