Supplementary Data Share Repurchase Program (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Feb. 12, 2016	Feb. 13, 2015
Disclosure of Repurchase Agreements [Abstract]
Stock repurchase program, authorized amount			$ 300.0	$ 300.0
Number of shares repurchased	8.5	8.5
Aggregate cost, including fees	$ 193.3	$ 172.3
Average price per share, including fees	$ 22.69	$ 20.36
Stock repurchase program, remaining authorized repurchase amount	$ 265.4