Income Taxes (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reconciliation of the change in the amount of unrecognized tax benefits
Balance at beginning of period	$ 25	$ 25	$ 25
Increase for tax positions taken in a prior year	1
(Decrease) increase for settlements	(26)
Balance at end of period		25	25
Unrecognized tax benefits interest accrued	0	0
Penalties accrued	0
Deferred assets
Unearned premium reserves	722	666
Discount on loss reserves	238	280
Accrued compensation	226	212
Difference in tax bases of invested assets	223	353
Sale of subsidiary	196	27
Other postretirement benefits	105	218
Pension		278
Alternative minimum tax credit carryforward		165
Other assets	96	92
Total deferred assets	1,806	2,291
Deferred liabilities
DAC	(1,077)	(917)
Unrealized net capital gains	(849)	(1,527)
Life and annuity reserves	(206)	(130)
Pension	(136)
Other liabilities	(324)	(314)
Total deferred liabilities	(2,592)	(2,888)
Net deferred liability before classification as held for sale	(786)	(597)
Deferred taxes classified as held for sale	(151)
Net deferred liability	(635)	(597)
Net operating loss carryforward	110
Components of income tax expense (benefit)
Current	869	295	14
Deferred	247	705	158
Total income tax expense	1,116	1,000	172
Income tax paid	500	280	32
Current income tax payable	203
Income tax receivable		$ 157
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation
Statutory federal income tax rate (as a percent)	35.00%	35.00%	35.00%
Tax-exempt income (as a percent)	(1.80%)	(3.00%)	(13.60%)
Tax credits (as a percent)	(2.20%)	(1.40%)	(2.10%)
Dividends received deduction (as a percent)	(0.60%)	(0.50%)	(1.80%)
Sale of subsidiary (as a percent)	2.00%
Other (as a percent)	0.50%	0.20%	0.40%
Effective income tax rate (as a percent)	32.90%	30.30%	17.90%