Capital Structure (Details) (USD $)	0 Months Ended	1 Months Ended	3 Months Ended		12 Months Ended								0 Months Ended		1 Months Ended								12 Months Ended		12 Months Ended																			12 Months Ended				12 Months Ended		12 Months Ended		12 Months Ended					12 Months Ended
	Jun. 20, 2013	Apr. 30, 2013	Dec. 31, 2013	Sep. 30, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Minimum	Dec. 31, 2013 Maximum	Dec. 31, 2013 Noncumulative Perpetual Preferred Stock	Jun. 12, 2013 Noncumulative Perpetual Preferred Stock	Dec. 31, 2013 Noncumulative Perpetual Preferred Stock Maximum director	Jun. 12, 2013 Noncumulative Perpetual Preferred Stock, Series A	Sep. 30, 2013 Noncumulative Perpetual Preferred Stock, Series C	Dec. 31, 2013 Noncumulative Perpetual Preferred Stock, Series D	Dec. 31, 2013 Commercial Paper	Dec. 31, 2012 Commercial Paper	Dec. 31, 2012 7.50% Debentures, due 2013	Dec. 31, 2013 5.00% Senior Notes, due 2014	Dec. 31, 2012 5.00% Senior Notes, due 2014	Dec. 31, 2013 6.20% Senior Notes, due 2014	Dec. 31, 2012 6.20% Senior Notes, due 2014	Dec. 31, 2013 6.75% Senior Debentures, due 2018	Dec. 31, 2012 6.75% Senior Debentures, due 2018	Dec. 31, 2013 6.75% Senior Debentures, due 2018 Maximum	Dec. 31, 2013 7.45% Senior Notes, due 2019	Dec. 31, 2012 7.45% Senior Notes, due 2019	Dec. 31, 2013 3.15% Senior Notes, due 2023	Jun. 07, 2013 3.15% Senior Notes, due 2023	Dec. 31, 2013 6.125% Senior Notes, due 2032	Dec. 31, 2012 6.125% Senior Notes, due 2032	Dec. 31, 2013 5.350% Senior Notes due 2033	Dec. 31, 2012 5.350% Senior Notes due 2033	Dec. 31, 2013 5.55% Senior Notes due 2035	Dec. 31, 2012 5.55% Senior Notes due 2035	Dec. 31, 2013 5.95% Senior Notes, due 2036	Dec. 31, 2012 5.95% Senior Notes, due 2036	Dec. 31, 2013 6.90% Senior Debentures, due 2038	Dec. 31, 2012 6.90% Senior Debentures, due 2038	Dec. 31, 2013 5.20% Senior Notes due 2042	Dec. 31, 2012 5.20% Senior Notes due 2042	Dec. 31, 2013 4.50% Senior Notes, due 2043	Jun. 07, 2013 4.50% Senior Notes, due 2043	Dec. 31, 2013 Subordinated Debentures	Dec. 31, 2013 5.10% Subordinated Debentures, due 2053	Dec. 31, 2013 5.75% Subordinated Debentures, due 2053	Aug. 08, 2013 5.75% Subordinated Debentures, due 2053	Dec. 31, 2013 6.125% Junior Subordinated Debentures, due 2067	Dec. 31, 2012 6.125% Junior Subordinated Debentures, due 2067	Dec. 31, 2013 6.50% Junior Subordinated Debentures, due 2067	Dec. 31, 2012 6.50% Junior Subordinated Debentures, due 2067	Dec. 31, 2013 Synthetic lease VIE obligations, floating rates, due 2014 store	Dec. 31, 2011 Synthetic lease VIE obligations, floating rates, due 2014	Dec. 31, 2012 Synthetic lease VIE obligations, floating rates, due 2014	Dec. 31, 2013 Federal Home Loan Bank ("FHLB") advances, due 2018	Dec. 31, 2012 Federal Home Loan Bank ("FHLB") advances, due 2018	Dec. 31, 2013 The Debentures	Jan. 10, 2013 5.10% Senior Notes due 2053
Debt outstanding:
Note stated interest rate (as a percent)																		7.50%	5.00%	5.00%	6.20%	6.20%	6.75%	6.75%		7.45%	7.45%	3.15%	3.15%	6.125%	6.125%	5.35%	5.35%	5.55%	5.55%	5.95%	5.95%	6.90%	6.90%	5.20%	5.20%	4.50%	4.50%		5.10%	5.75%	5.75%	6.125%	6.125%	6.50%	6.50%							5.10%
Property and equipment, net			$ 1,024,000,000		$ 1,024,000,000	$ 989,000,000																																														$ 29,000,000		$ 30,000,000
Total long-term debt			6,201,000,000		6,201,000,000	6,057,000,000												250,000,000	650,000,000	650,000,000	300,000,000	300,000,000	177,000,000	250,000,000		317,000,000	700,000,000	500,000,000		159,000,000	250,000,000	323,000,000	400,000,000	546,000,000	800,000,000	386,000,000	650,000,000	165,000,000	250,000,000	72,000,000	500,000,000	500,000,000			500,000,000	800,000,000		252,000,000	500,000,000	500,000,000	500,000,000	44,000,000		44,000,000	10,000,000	13,000,000
Total debt			6,201,000,000		6,201,000,000	6,057,000,000
Redemption price as percentage of principal amount plus accrued and unpaid interest					100.00%
Face amount of debt issued																													500,000,000														500,000,000				800,000,000											500,000,000
Repurchased principal amounts of debt	1,830,000,000		73,000,000	73,000,000	73,000,000
Loss on extinguishment of debt	(480,000,000)		(11,000,000)	(11,000,000)	(491,000,000)
Minimum principal outstanding amount for redemption of debt in whole or in part																																												25,000,000
Period of issuance of common stock prior to dividend declaration date during which dividend declaration is prohibited					90 days
Period after occurrence of certain tax and rating agency events in which redemption of debt in whole permissible										90 days																																		90 days
Interest on debentures payment terms																																												three-month LIBOR	three-month LIBOR	three-month LIBOR		three-month LIBOR		three-month LIBOR
Interest rate spread over LIBOR (as a percent)																																												3.165%	3.165%	2.938%		1.935%		2.12%
Maximum period for deferment of interest payment																																												5 years													10 years
Reserved common stock authorized and unissued for debentures obligations (in shares)																																																									75,000,000
Threshold percentage of repurchase or redemption of outstanding principal debentures for non applicability of promises and covenants contained in the new RCC																							10.00%
Period within which threshold percentage of outstanding principal of debentures is to be purchased for non applicability of promises and covenants contained in the new RCC																							1 year
Percentage of repurchase or redemption of outstanding principal debentures within specified period for non applicability of promises and covenants contained in the new RCC																									25.00%
Specified period within which percentage of outstanding principal of debentures is to be purchased for non applicability of promises and covenants contained in the new RCC																							10 years
Maximum number of stores acquired																																																				19
Renewal term for synthetic lease																																																					3 years
Unsecured revolving credit facility			1,000,000,000		1,000,000,000
Commercial Paper maximum borrowing capacity			1,000,000,000		1,000,000,000
Credit facility initial term					5 years
Terms for extension of credit facility					The Company has the option to extend the expiration of its initial five year term by one year at the first and second anniversary of the facility, upon approval of existing or replacement lenders.
Credit facility extended term		1 year
Additional borrowing capacity under credit facility increase provision			500,000,000		500,000,000
Maximum debt to capital ratio allowed under credit facility covenant (as a percent)					37.50%
Amount outstanding under credit facility			0		0	0
Amount of commercial paper outstanding																0	0
Interest paid on debt					361,000,000	366,000,000	363,000,000
Common stock
Common stock, shares issued			900,000,000		900,000,000	900,000,000
Common stock, shares outstanding			449,000,000		449,000,000	479,000,000
Treasury stock, shares			451,000,000		451,000,000	421,000,000
Reacquired shares					38,000,000
Average cost of reacquired shares (in dollars per share)					$ 49.29
Reissued shares under equity incentive plans					8,000,000
Preferred stock
Preferred stock, issued shares			32,300		32,300	0							11,500	15,400	5,400
Preferred stock stated dividend rate (as a percent)													5.625%	6.75%	6.625%
Preferred stock, par value (in dollars per share)			$ 1		$ 1	$ 1							$ 1.00	$ 1.00	$ 1.00
Preferred stock, shares liquidation preference (in dollars per share)													$ 25,000	$ 25,000	$ 25,000
Gross proceeds from issue of preferred stock													$ 287,500,000	$ 385,000,000	$ 135,000,000
Additional members of the board of directors												2
Preferred stock, redemption price (in dollars per share)										$ 25,000	$ 25,000
Collective risk-based capital ratios of subsidiaries as a percentage of net written premiums of insurance business								80.00%
Risk-based capital ratios as a percentage of action level risk-based capital									175.00%
Percentage of decline in consolidated shareholders' equity from benchmark quarter								20.00%
Percentage by which consolidated shareholders' equity should increase or decrease to avoid restriction on dividends									20.00%