Consolidated Balance Sheets (USD $) In Millions, except Per Share data, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Investments [Abstract]
Fixed maturities, at fair value (amortized cost, $14,315; $15,481)	$ 15,767	$ 17,705
Equity securities, at fair value (cost, $130; $121)	122	111
Commercial mortgage loans	2,570	2,851
Policy loans	1,522	1,501
Real estate	85	83
Other long-term investments	1,269	1,255
Short-term investments	296	154
Total investments	21,631	23,660
Cash and cash equivalents	3,209	2,978
Accrued investment income	233	258
Premiums, accounts and notes receivable, net	1,977	1,777
Reinsurance recoverables	7,407	6,256
Deferred policy acquisition costs	1,262	1,198
Property and equipment	1,191	1,120
Deferred income taxes, net	335	374
Goodwill	5,986	6,001
Other assets, including other intangibles	2,633	2,355
Separate account assets	7,965	7,757
Total assets	53,829	53,734
Liabilities
Contractholder deposit funds	8,531	8,508
Future policy benefits	9,306	9,265
Unpaid claims and claim expenses	4,161	4,062
Global Health Care medical claims payable	2,003	1,856
Unearned premiums and fees	587	549
Total insurance and contractholder liabilities	24,588	24,240
Accounts payable, accrued expenses and other liabilities	6,217	6,667
Short-term debt	153	201
Long-term debt	5,030	4,986
Separate account liabilities	7,965	7,757
Total liabilities	43,953	43,851
Contingencies - Note 17
Redeemable noncontrolling interest	101	114
Shareholders' Equity
Common stock (par value per share, $0.25; shares issued,366; authorized, 600)	92	92
Additional paid-in capital	3,326	3,295
Net unrealized appreciation, fixed maturities	542	883
Net unrealized appreciation, equity securities	6	4
Net unrealized depreciation, derivatives	(19)	(28)
Net translation of foreign currencies	(5)	69
Postretirement benefits liability adjustment	(1,538)	(1,599)
Accumulated other comprehensive loss	(1,014)	(671)
Retained earnings	12,806	12,330
Less treasury stock, at cost	(5,435)	(5,277)
Total shareholders' equity	9,775	9,769
Total liabilities and equity	$ 53,829	$ 53,734
Shareholders' Equity Per Share	$ 34.46	$ 34.18