Share-Based Compensation Narrative (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	0	0	0
Number of shares available for grant under Incentive Plans	17,000
Employee Service Share-based Compensation, Cash Received from Exercise of Stock Options	$ 26
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum term (in years) that awards will be granted	10 years
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of stock options exercised	$ 15	$ 13	$ 12
Employee Stock Option [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	1 year
Employee Stock Option [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	4 years
Restricted Stock and Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value	$ 11.94	$ 18.98	$ 13.49
Total fair value of awards vested during the period	$ 37	$ 52	$ 61
Unrecognized compensation expense	$ 120
Unrecognized compensation expense, recognition period	2 years
Restricted Stock and Restricted Stock Units (RSUs) [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	2 years
Restricted Stock and Restricted Stock Units (RSUs) [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	5 years
Performance units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Award vesting	225.00%
Weighted-average grant date fair value	$ 10.45	$ 14.31	$ 10.81
Total fair value of awards vested during the period		$ 11	$ 8
Unrecognized compensation expense	$ 13
Unrecognized compensation expense, recognition period	1 year
Risk-free interest rate	0.51%
Volatility rate	46.10%
Dividend yield	0.00%
Shares issued for share-based compensation awards (in shares)	0	541	1,300