CONSOLIDATED STATEMENT OF CHANGES IN SHAREHOLDERS' EQUITY (UNAUDITED) (USD $) In Millions, unless otherwise specified	Total	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]
Balance at beginning of period at Dec. 31, 2013		$ 1,565
Balance at beginning of period at Dec. 31, 2013			0	14,106	952	(159)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Capital contribution from parent				0
Employee benefit plans				6
Net income	104				104
Cash dividends declared on preferred stock					(18)
Other comprehensive income (loss), net of tax	111					111
Balance at end of period at Mar. 31, 2014	16,667	1,565
Balance at end of period at Mar. 31, 2014	15,102		0	14,112	1,038	(48)
Balance at beginning of period at Dec. 31, 2014	16,967	1,565
Balance at beginning of period at Dec. 31, 2014	15,402		0	14,170	1,233	(1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Capital contribution from parent				4,000
Employee benefit plans				4
Net income	164				164
Cash dividends declared on preferred stock					(18)
Other comprehensive income (loss), net of tax	(46)					(46)
Balance at end of period at Mar. 31, 2015	21,071	1,565
Balance at end of period at Mar. 31, 2015	$ 19,506		$ 0	$ 18,174	$ 1,379	$ (47)