Stock-Based Compensation (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-based compensation expense, before tax (in dollars)	$ 64	$ 69	$ 196	$ 204
Stock-based compensation awards
Granted, Stock options (in shares)			4,276,060	3,224,203
Fair Value Per Award, Stock options (in dollars per share)			$ 28.34	$ 39.20
Stock price on the date of grant (in dollars per share)	$ 89.75	$ 110.09	$ 89.75	$ 110.09
Assumptions used in determining the fair value of the stock-based awards
Weighted-average dividend yield (as a percent)			2.13%	2.16%
Weighted-average volatility (as a percent)			30.60%	35.00%
Volatilities, low end of range (as a percent)			23.40%	33.30%
Volatilities, high end of range (as a percent)			40.60%	40.40%
Risk-free interest rates, low end of range (as a percent)			0.16%	0.17%
Risk-free interest rates, high end of range (as a percent)			1.88%	2.00%
Weighted-average expected lives (in years)			8 years	7 years
Unrecognized compensation cost related to nonvested stock-based compensation awards (in dollars)	$ 232		$ 232
Term of amortization of unrecognized compensation cost over weighted-average remaining requisite service periods (in years)			1 year 11 months
RSUs
Stock-based compensation awards
Granted (in shares)			1,614,870	1,429,939
Fair Value Per Award (in dollars per share)			$ 84.05	$ 104.61