Accumulated Other Comprehensive Income (Loss) by Component (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), beginning balance	$ 400	$ 442
Transfer to net assets held for sale		0
Other comprehensive income (loss), before reclassifications	24	276
Amounts reclassified from accumulated other comprehensive income (loss) after tax (expense) benefit	3	26
Other comprehensive income (loss) after tax (expense) benefit	21	250
Accumulated other comprehensive income (loss), ending balance	421	692
Tax (expense) benefit on amounts reclassified from accumulated other comprehensive income (loss)	3	(13)
Tax (expense) benefit on other comprehensive income (loss)	(65)	(139)
Net unrealized gains (losses) on investments with OTTI losses [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), beginning balance	36	26
Transfer to net assets held for sale		(5)
Other comprehensive income (loss), before reclassifications	(1)	12
Amounts reclassified from accumulated other comprehensive income (loss) after tax (expense) benefit	0	0
Other comprehensive income (loss) after tax (expense) benefit	(1)	12
Accumulated other comprehensive income (loss), ending balance	35	33
Tax (expense) benefit on amounts reclassified from accumulated other comprehensive income (loss)	0	0
Tax (expense) benefit on other comprehensive income (loss)	0	(6)
Net unrealized gains (losses) on other investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), beginning balance	942	692
Transfer to net assets held for sale		(17)
Other comprehensive income (loss), before reclassifications	121	264
Amounts reclassified from accumulated other comprehensive income (loss) after tax (expense) benefit	9	27
Other comprehensive income (loss) after tax (expense) benefit	112	237
Accumulated other comprehensive income (loss), ending balance	1,054	912
Tax (expense) benefit on amounts reclassified from accumulated other comprehensive income (loss)	0	(14)
Tax (expense) benefit on other comprehensive income (loss)	(62)	(127)
Accumulated Net Unrealized Gains Losses on discontinued operations [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), beginning balance		0
Transfer to net assets held for sale		22
Other comprehensive income (loss), before reclassifications		8
Amounts reclassified from accumulated other comprehensive income (loss) after tax (expense) benefit		0
Other comprehensive income (loss) after tax (expense) benefit		8
Accumulated other comprehensive income (loss), ending balance		30
Tax (expense) benefit on amounts reclassified from accumulated other comprehensive income (loss)		0
Tax (expense) benefit on other comprehensive income (loss)		(5)
Pension and postretirement benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), beginning balance	(633)	(426)
Transfer to net assets held for sale		0
Other comprehensive income (loss), before reclassifications	0	0
Amounts reclassified from accumulated other comprehensive income (loss) after tax (expense) benefit	(6)	(1)
Other comprehensive income (loss) after tax (expense) benefit	6	1
Accumulated other comprehensive income (loss), ending balance	(627)	(425)
Tax (expense) benefit on amounts reclassified from accumulated other comprehensive income (loss)	3	1
Tax (expense) benefit on other comprehensive income (loss)	(3)	(1)
Cumulative foreign currency translation adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), beginning balance	55	150
Transfer to net assets held for sale		0
Other comprehensive income (loss), before reclassifications	(96)	(8)
Amounts reclassified from accumulated other comprehensive income (loss) after tax (expense) benefit	0	0
Other comprehensive income (loss) after tax (expense) benefit	(96)	(8)
Accumulated other comprehensive income (loss), ending balance	(41)	142
Tax (expense) benefit on amounts reclassified from accumulated other comprehensive income (loss)	0	0
Tax (expense) benefit on other comprehensive income (loss)	$ 0	$ 0