Equity (Details 5) - Stock options - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Shares
Outstanding at the beginning of the period (in shares)	0.4
Exercised (in shares)	(0.1)
Outstanding at the ending of the period (in shares)	0.3	0.4
Exercisable at the end of the period (in shares)	0.3
Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)	$ 45.67
Exercised (in dollars per share)	46.73
Outstanding at the ending of the period (in dollars per share)	45.41	$ 45.67
Exercisable at the end of the period (in dollars per share)	$ 45.41
Weighted Average Remaining Contractual Life (in years)
Outstanding at the end of the period (in years)	3 years 10 months 24 days
Exercisable at the end of the period (in years)	3 years 10 months 24 days
Aggregate Intrinsic Value
Exercised	$ 5.8	$ 15.4	$ 13.1