Stock-Based Compensation (Details 3) (USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended	12 Months Ended
	May 31, 1997	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Share- based compensation assumptions
Stock-based compensation programs expense		$ 253	$ 274	$ 217
Stock Option Program
Stock Option Program
Balance at the beginning of the period		70,335,044	74,268,165	75,452,722
Granted - Annual		5,514,500	5,788,313	6,649,672
Granted - Progressive (Reload)		237,839	188,105	68,189
Granted - Other		8,953	27,911	4,654
Exercised		(11,625,863)	(9,678,654)	(6,930,544)
Canceled		(322,058)	(258,796)	(976,528)
Balance at the end of the period		64,148,415	70,335,044	74,268,165
Weighted average exercise price - Beginning balance		$ 74.80	$ 72.39	$ 71.96
Weighted average exercise price - Annual grants		$ 89.46	$ 78.79	$ 53.93
Weighted average exercise price - Progressive (Reload)		$ 94.02	$ 88.67	$ 77.37
Weighted average exercise price - Other		$ 86.71	$ 82.13	$ 50.85
Weighted average exercise price - Exercised		$ 68.47	$ 59.11	$ 49.83
Weighted average exercise price - Canceled		$ 75.09	$ 70.76	$ 73.50
Weighted average exercise price - Ending balance		$ 77.28	$ 74.80	$ 72.39
Options exercisable		52,644,364	58,201,617	62,414,398
Options exercisable, exercise price		$ 76.90	$ 75.87	$ 73.73
Weighted Average Remaining Contractual Life for options outstanding (in months)		54
Aggregate Intrinsic Value for options outstanding		426
Weighted Average Remaining Contractual Life for options exercisable (in months)		44
Aggregate Intrinsic Value for options exercisable		352
Compensation expense yet to be recognized for stock options		57
Weighted average life of remaining vesting period for stock options (in years)		1.7
Total intrinsic value of stock options exercised		287	263	108
Cash received from options exercised		796	571	345
Tax benefit realized from exercise of stock options		96	93	38
Stock Option Program | Annual
Share- based compensation assumptions
Weighted average exercise price		$ 89.47	$ 78.72	$ 54.11
Risk-free interest rate (as a percent)		2.80%	2.80%	2.20%
Dividend yield (as a percent)		2.60%	2.50%	2.30%
Expected volatility (as a percent)		22.00%	25.70%	30.30%
Expected life (in months)		72	72	71
Black-Scholes fair value		$ 16.10	$ 16.50	$ 13.00
Stock Option Program | Progressive (Reload)
Share- based compensation assumptions
Weighted average exercise price		$ 93.94	$ 86.72	$ 77.83
Risk-free interest rate (as a percent)		0.40%	0.60%	1.40%
Dividend yield (as a percent)		2.60%	2.50%	2.00%
Expected volatility (as a percent)		21.50%	33.20%	30.70%
Expected life (in months)		15	17	32
Black-Scholes fair value		$ 7.49	$ 12.01	$ 14.47
General employees' Stock Purchase Plan (GESPP)
Stock Option Program
Granted - Annual		1,433,609	1,325,579	1,655,936
Exercised		(1,433,609)	(1,325,579)	(1,655,936)
Weighted average exercise price - Annual grants		$ 73.67	$ 70.57	$ 50.58
Weighted average exercise price - Exercised		$ 73.67	$ 70.57	$ 50.58
Share- based compensation assumptions
Black-Scholes fair value		$ 13.00	$ 12.45	$ 8.93
Option price, percentage of market value at date of grant	85.00%
Option price, discount from market value at date of grant		15.00%
Number of shares authorized	30,000,000
Number of shares available for grant		2,900,751	4,334,360	5,659,939
Stock-based compensation programs expense		$ 19	$ 17	$ 15