Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Supplemental Schedule of Noncash Investing and Financing Activities
Cash dividends declared, but not yet paid	$ 4.0	$ 4.1
Beneficial interest obtained in exchange for accounts receivable sold	$ 121.3	$ 74.0