Earnings Per Share and Share Repurchases (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Earnings Per Share [Abstract]
Income from continuing operations	$ 86	$ 89	$ 148	$ 148
Income (loss) from discontinued operations, net of tax	0	13	(1)	4
Net income applicable to common shares	86	102	147	152
Weighted Average Number of Shares Outstanding, Diluted [Abstract]
Weighted average outstanding shares of common stock	165.2	159.0	164.5	158.6
Dilutive effect of employee stock options and restricted stock	3.6	4.9	3.6	4.5
Common stock and common stock equivalents	168.8	163.9	168.1	163.1
Basic earnings per share: [Abstract]
Basic (in dolars per share)	$ 0.52	$ 0.56	$ 0.90	$ 0.93
From discontinued operations	$ 0.00	$ 0.08	$ (0.01)	$ 0.03
Basic (in dollars per share)	$ 0.52	$ 0.64	$ 0.89	$ 0.96
Diluted earnings per share: [Abstract]
Diluted (in dollars per share)	$ 0.51	$ 0.54	$ 0.88	$ 0.91
From discontinued operations	$ 0.00	$ 0.08	$ (0.01)	$ 0.02
Diluted (in dollars per share)	$ 0.51	$ 0.62	$ 0.87	$ 0.93
Shares repurchased
Stock Repurchased and Retired During Period, Shares	0	0	0	0
Stock Repurchased and Retired During Period, Value	$ 0	$ 0	$ 0	$ 0