Stock Compensation (Tables)

12 Months Ended

Dec. 31, 2015

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

Award activity — (shares in millions)



	Options				SARs				RSUs				PSUs
			Weighted- Average				Weighted- Average				Weighted- Average Grant-Date				Weighted- Average Grant-Date
Outstanding at	Shares		Exercise Price		Shares		Exercise Price		Shares		Fair Value		Shares		Fair Value
December 31, 2014	1.9		$	14.46	0.4		$	15.18	1.5		$	18.18	0.3		$	24.36
Granted									0.7		21.68		0.4		22.97
Exercised or vested	(0.1	)	13.83		(0.1	)	12.53		(0.7	)	17.21		(0.1	)	24.48
Forfeited or expired									(0.2	)	20.46		(0.2	)	24.57
December 31, 2015	1.8		14.50		0.3		15.46		1.3		20.09		0.4		22.92



	2015		2014		2013
Weighted-average grant-date fair value per share granted
Stock options	N/A		N/A		$	7.46
SARs	N/A		N/A		7.45
Intrinsic value of awards exercised or vested
Stock options / SARs	$	1	$	7	$	14
RSUs / PSUs	16		8		5

Key Assumptions as Part of Black-Scholes Option Pricing Model [Table Text Block]

We estimated fair values for options and SARs at the date of grant using the following key assumptions as part of the Black-Scholes option pricing model. The expected term was estimated using the simplified method because the limited period of time our common stock had been publicly traded provided insufficient historical exercise data. The risk-free rate was based on U.S. Treasury security yields at the time of grant. The dividend yield was calculated by dividing the expected annual dividend by the average stock price of our common stock over the prior year. The expected volatility was estimated using a combination of the historical volatility of similar entities and the implied volatility of our exchange-traded options.



	Options		SARs
	2013		2013
Expected term (in years)	6.0		6.0
Risk-free interest rate	1.07	%	1.07	%
Dividend yield	1.41	%	1.41	%
Expected volatility	55.8	%	55.8	%

Key Assumptions as Part of Monte Carlo Simulation Model [Table Text Block]

For the portion of the PSU award based on shareholder returns, we estimated the fair value at grant date using various assumptions as part of a Monte Carlo simulation. The expected term represents the period from the grant date to the end of the performance period. The risk-free interest rate was based on U.S. Treasury constant maturity rates at the grant date. The dividend yield was calculated by dividing the expected annual dividend by the average stock price over the prior year. The expected volatility was based on historical volatility using daily stock price observations.



	PSUs
	2015		2014
Expected term (in years)	3.0		3.0
Risk-free interest rate	0.89	%	0.64	%
Dividend yield	0.98	%	1.02	%
Expected volatility	33.9	%	43.6	%

Outstanding Awards Expected to Vest [Table Text Block]

Outstanding awards expected to vest and exercisable or convertible at December 31, 2015 — (shares in millions)



	Equity Awards Outstanding Expected to Vest						Equity Awards Outstanding That are Exercisable or Convertible
				Weighted-Average						Weighted-Average
	Shares	Aggregate Intrinsic Value		Exercise Price		Remaining Contractual Life in Years	Shares	Aggregate Intrinsic Value		Exercise Price		Remaining Contractual Life in Years
Options / SARs	2.1	$	2	$	14.66	5.9	1.9	$	2	$	14.49	5.8
RSUs / PSUs	1.8	24		—		1.3	0.3	4		—		0.9