Stockholders' Equity (Details 2 ) (USD $) In Millions, except Per Share data, unless otherwise specified	1 Months Ended			12 Months Ended			0 Months Ended
	Feb. 28, 2014	Feb. 28, 2013	May 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 30, 2014	Sep. 30, 2014	Jun. 30, 2014	Apr. 01, 2014	Dec. 30, 2013	Sep. 30, 2013	Jul. 01, 2013	Apr. 01, 2013	Dec. 31, 2012	Oct. 01, 2012	Jul. 02, 2012	Mar. 30, 2012	Dec. 31, 2011
Common stock
Reconciliation of Outstanding Shares
Outstanding shares at beginning of period				295.2	293.8	301.1
Shares issued				3.4	5.8	3.2
Treasury stock acquired				(4.7)	(4.4)	(10.5)
Outstanding shares at end of period				293.9	295.2	293.8									293.8
Common stock share repurchase disclosures
Share repurchase program, maximum authorized amount (in dollars)	$ 200.0	$ 150.0	$ 200.0
Series A | Preferred stock
Reconciliation of Outstanding Shares
Outstanding shares at beginning of period				3.0											3.0				3.0
Outstanding shares at end of period				3.0															3.0
Preferred Stock
Preferred stock dividend rate per annum (as a percent)				5.563%
Preferred stock redemption price (in dollars per share)				100
Preferred stock aggregate redemption amount				300.0
Preferred stock dividend (in dollars per share)							$ 1.39	$ 1.39	$ 1.39	$ 1.39	$ 1.39	$ 1.39	$ 1.39	$ 1.39	$ 1.39	$ 1.39	$ 1.39	$ 1.39
Series B | Preferred stock
Reconciliation of Outstanding Shares
Outstanding shares at beginning of period				10.0											10.0				10.0
Outstanding shares at end of period				10.0															10.0
Preferred Stock
Preferred stock dividend rate per annum (as a percent)				6.518%
Preferred stock redemption price (in dollars per share)				25
Preferred stock aggregate redemption amount				250.0
Preferred stock dividend (in dollars per share)							$ 0.41	$ 0.41	$ 0.41	$ 0.41	$ 0.41	$ 0.41	$ 0.41	$ 0.41	$ 0.41	$ 0.41	$ 0.41	$ 0.41