Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2016

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,
	2016		2015		2014
Stock-based compensation expense:
Restricted stock	$	52	$	47	$	43
Performance awards	15		11		15
Stock options	1		1		2
Total stock-based compensation expense	$	68	$	59	$	60
Tax benefit recognized on stock-based compensation expense	$	24	$	21	$	21
Tax benefit realized for tax deductions resulting from exercises and vestings	33		66		64
Effect of tax deductions in excess of recognized stock-based compensation expense (a)	22		44		47

_______________________________

^(a)  Effective January 1, 2016, the effect of tax deductions in excess of recognized stock-based compensation expense is reported as an operating cash flow. These amounts were previously reported as financing cash flows.

Summary of restricted stock awards

The following table reflects activity related to our restricted stock (in millions, except per share data):

	Year Ended December 31,
	2016		2015		2014
Weighted-average grant-date fair value per share of restricted stock granted	$	59.00	$	70.07	$	49.40
Fair value of restricted stock vested	46		69		60

The fair value of each restricted stock per share is equal to the market price of our common stock. 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, 2016	1,551,440		$	57.15
Granted	1,004,935		59.00
Vested	(978,845	)	53.40
Forfeited	(10,580	)	57.37
Nonvested shares as of December 31, 2016	1,566,950		60.68

Summary of performance awards

Performance awards converted during the year ended December 31, 2016 were as follows:

	Vested Awards Converted	Actual Conversion Rate	Number of Shares Issued
2012 awards	96,844	200%	193,688
2013 awards	78,411	200%	156,822
2014 awards	49,871	200%	99,742
Total	225,126		450,252

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

	Nonvested Awards		Weighted- Average Grant-Date Fair Value Per Share
Awards outstanding as of January 1, 2016	408,425		$	66.23
Granted	170,327		88.79
Vested	(225,126	)	47.71
Forfeited	(15,237	)	91.88
Awards outstanding as of December 31, 2016	338,389		88.75