Income Taxes (Components of Tax Provision (Benefit)) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Taxes currently payable:
Federal									$ 320.7	$ 489.4	$ 352.6
State and local									63.1	56.3	45.4
Deferred income taxes									(28.7)	(273.8)	(245.1)
Total U.S. tax provision									355.1	271.9	152.9
International:
Taxes currently payable									71.1	54.1	64.1
Deferred income taxes									(4.7)	1.5	(1.5)
Total international tax provision									66.4	55.6	62.6
Total provision	$ 184.5	$ 14.2	$ 114.6	$ 108.2	$ 96.9	$ 69.0	$ 109.0	$ 52.6	421.5	327.5	$ 215.5
Undistributed earnings of foreign subsidiaries	9,667.0								9,667.0
Unremitted earnings of international subsidiaries	900.0								900.0
Deferred tax liability on foreign earnings	$ 316.5				$ 316.5				$ 316.5	$ 316.5