Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2012

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

Schedule of stock-based compensation expense and tax benefits

The following table reflects activity related to our stock-based compensation arrangements (in millions):

	Year Ended December 31,
	2012		2011		2010
Stock-based compensation expense	$	58	$	58	$	54
Tax benefit recognized on stock-based compensation expense	20		20		19
Tax benefit realized for tax deductions resulting from exercises and vestings	45		35		23
Effect of tax deductions in excess of recognized stock-based compensation expense reported as a financing cash flow	27		23		11

Summary of weighted-average assumptions used in fair value measurements

A summary of the weighted-average assumptions used in our fair value measurements is presented in the table below.

	Year Ended December 31,
	2012		2011		2010
Expected life in years	6.0		6.0		6.0
Expected volatility	49.11	%	49.30	%	48.21	%
Expected dividend yield	2.39	%	2.28	%	1.05	%
Risk-free interest rate	0.85	%	1.44	%	1.83	%

Summary of stock option awards

A summary of the status of our stock option awards is presented in the table below.

	Number of Stock Options		Weighted- Average Exercise Price Per Share		Weighted- Average Remaining Contractual Term	Aggregate Intrinsic Value
					(in years)	(in millions)
Outstanding as of January 1, 2012	19,906,586		$	27.11
Granted	262,170		29.23
Exercised	(4,738,312	)	13.67
Expired	(2,196,876	)	47.72
Forfeited	(18,840	)	32.29
Outstanding as of December 31, 2012	13,214,728		28.54		3.3	$	157
Exercisable as of December 31, 2012	12,594,488		28.65		3.0	152

Summary of restricted stock awards

A summary of the status of our restricted stock awards is presented in the table below.

	Number of Shares		Weighted- Average Grant-Date Fair Value Per Share
Nonvested shares as of January 1, 2012	3,249,090		$	22.28
Granted	1,459,317		28.90
Vested	(1,736,379	)	23.67
Forfeited	(51,740	)	22.07
Nonvested shares as of December 31, 2012	2,920,288		24.76

Summary of performance awards

A summary of the status of our performance awards considered granted is presented below.

	Nonvested Awards		Vested Awards
Awards outstanding as of January 1, 2012	691,191		24,635
Granted	547,140		—
Vested	(222,250	)	222,250
Forfeited	(26,667	)	(37,969	)
Awards outstanding as of December 31, 2012	989,414		208,916

There were three tranches of performance awards granted during the year ended December 31, 2012 as follows:

	Awards Granted	Expected Conversion Rate	Fair Value Per Share
Third tranche of 2010 awards	208,917	100%	$	28.53
Second tranche of 2011 awards	233,350	50%	28.53
First tranche of 2012 awards	104,873	75%	28.53
Total	547,140