Share-Based Compensation Plans (Details 3) (USD $) In Millions, except Per 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]
Closing share price (in dollars per share)	$ 74.44		$ 74.44
Aggregate intrinsic value of options outstanding	$ 163		$ 163
Aggregate intrinsic value of exercisable options outstanding	156		156
Aggregate intrinsic value of stock options exercised	14	23	53	47
Cash received from the exercise of stock options	14	29	55	80
Tax benefit realized from the exercise of stock options	3	5	10	8
Unamortized deferred compensation expense	$ 373		$ 373
Remaining weighted-average amortization period (in years)			2 years 1 month 12 days