Share-Based Compensation (Stock Option Activity) (Details) (Stock Options, USD $) In Millions, except Share data in Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
Stock Options
Options (Number of Shares):
Outstanding at beginning of period	6,865
Exercised	(265)
Forfeited and expired	(883)
Granted	1,345
Outstanding at end of period	7,062
Vested and expected to vest at end of period	6,759
Eligible for exercise at end of period	4,849
Weighted Average Exercise Price (in dollars per share):
Outstanding at beginning of period	$ 14.91
Exercised	$ 10.63
Forfeited and expired	$ 16.15
Granted	$ 14.46
Outstanding at end of period	$ 14.83
Vested and expected to vest at end of period	$ 14.89
Eligible for exercise at end of period	$ 15.61
Outstanding, weighted average remaining contractual term (in years)	60 months
Vested and expected to vest, weighted average remaining contractual term (in years)	59 months
Eligible for exercise, weighted average remaining contractual term (in years)	41 months
Outstanding, intrinsic value	$ 8
Vested and expected to vest, intrinsic value	8
Eligible for exercise, intrinsic value	$ 6