Acquisition (Details 2) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Acquisition
Total revenues - Pro forma	$ 9,339.4	$ 9,424.4	$ 8,840.3
Net income (loss) - Pro forma	$ 956.6	$ 939.3	$ 753.2
Basic earnings (loss) per common share (in dollars per share) - Pro forma	$ 3.25	$ 3.16	$ 2.39
Diluted earnings (loss) per common share (in dollars per share) - Pro forma	$ 3.21	$ 3.13	$ 2.37