Condensed Financial Statements Of Parent Company Condensed Financial Statements Of Parent Company Condensed Statements Of Comprehensive Income (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Condensed Financial Statements, Captions [Line Items]
Net income (loss)	$ 122	$ 131	$ 110	$ 154	$ 192	$ 111	$ 32	$ 86	$ 517	$ 421	$ 164
Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Actuarial Loss And Prior Service Cost Arising During Period Before Tax									83	(13)	(25)
Other Comprehensive Income (Loss), Tax									(202)	(124)	(71)
Other Comprehensive Income (Loss), Net of Tax									375	228	132
COMPREHENSIVE INCOME									892	649	296
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period Held by Subsidiaries and Other, before Tax									494	365	228
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Tax, Portion Attributable to Parent									83	(13)	(25)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent									577	352	203
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent									202	124	71
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Net income (loss)									517	421	164
Unrealized gains on investments available-for-sale									303	67	59
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period Held by Subsidiaries, before Tax									240	361	250
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax									(21)	(34)	(15)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI Held by Subsidiaries, before Tax									(62)	(8)	(55)
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Other, before Tax									(1)	5	1
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Other Subsidiaries, before Tax									$ 35	$ (26)	$ (12)