Other Comprehensive Income and Accumulated Other Comprehensive Income (details) - Reclassifications (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Reclassification adjustment impacting realized gains on the income statement	$ (10)	[1]	$ (1)	[1]
Reclassification adjustment impacting general and administrative expense on the income statement	992		881
Total reclassifications	(1,148)		(1,470)
Income tax benefit (expense)	(315)		(418)
Amounts reclassified from accumulated other comprehensive income, net of taxes	(833)		(1,052)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Total reclassifications	5		13
Income tax benefit (expense)	2		6
Amounts reclassified from accumulated other comprehensive income, net of taxes	3		7
Changes in Net Unrealized Gains on Investment Securities Having No Credit Losses Recognized in the Consolidated Statement of Income [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Reclassification adjustment impacting realized gains on the income statement	(18)		(5)
Income tax benefit (expense)	(6)		(2)
Amounts reclassified from accumulated other comprehensive income, net of taxes	(12)		(3)
Changes in Net Unrealized Gains on Investment Securities Having Credit Losses Recognized in the Consolidated Statement of Income [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Reclassification adjustment impacting realized gains on the income statement			3
Income tax benefit (expense)			1
Amounts reclassified from accumulated other comprehensive income, net of taxes			2
Net Benefit Plan Assets and Obligations Recognized in Shareholders' Equity [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Reclassification adjustment impacting general and administrative expense on the income statement	23		15
Income tax benefit (expense)	8		7
Amounts reclassified from accumulated other comprehensive income, net of taxes	$ 15		$ 8

[1] Total other-than-temporary impairment (OTTI) losses were $(4) million and $(7) million for the three months ended March 31, 2015 and 2014, respectively. Of total OTTI, credit losses of $(3) million and $(9) million for the three months ended March 31, 2015 and 2014, respectively, were recognized in net realized investment gains. In addition, unrealized gains (losses) from other changes in total OTTI of $(1) million and $2 million for the three months ended March 31, 2015 and 2014, respectively, were recognized in other comprehensive income (loss) as part of changes in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income.