Stock Options and Other Share-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2011

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Fair market values of stock options and stock appreciation rights granted

	Year ended December 31
	2011			2010			2009
Stock Options
Expected term in years1		6.2			6.1			6.0
Volatility2		31.0	%		30.8	%		30.2	%
Risk-free interest rate based on zero coupon U.S. treasury note		2.6	%		2.9	%		2.1	%
Dividend yield		3.6	%		3.9	%		3.2	%
Weighted-average fair value per option granted	$	21.24		$	16.28		$	15.36
Restored Options
Expected term in years1		1.2			1.2			1.2
Volatility2		20.6	%		38.9	%		45.0	%
Risk-free interest rate based on zero coupon U.S. treasury note		0.7	%		0.6	%		1.1	%
Dividend yield		3.4	%		3.8	%		3.5	%
Weighted-average fair value per option granted	$	7.55		$	12.91		$	12.38

1	Expected term is based on historical exercise and postvesting cancellation data.
2	Volatility rate is based on historical stock prices over an appropriate period, generally equal to the expected term.

Summary of option activity

						Weighted-
				Weighted-		Average
				Average		Remaining	Aggregate
	Shares			Exercise		Contractual	Intrinsic
	(Thousands)			Price		Term	Value
Outstanding at January 1, 2011		74,852		$	67.04
Granted		14,260		$	94.46
Exercised		(15,844	)	$	60.20
Restored		33		$	103.96
Forfeited		(953	)	$	85.79
Outstanding at December 31, 2011		72,348		$	73.71	6.4 yrs	$	2,365
Exercisable at December 31, 2011		45,494		$	67.84	5.3 yrs	$	1,755