Reportable Business Segments and International Operations, Reconciliation of Segment Assets (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of segment assets to consolidated total assets
Segment assets excluding goodwill	$ 4,784.6	$ 4,743.9
Goodwill	3,678.8	2,692.9	$ 2,616.7
Other assets	35.3	21.6
Total assets	$ 8,498.7	$ 7,458.4