Equity, Cash Dividends on Shares of Common Stock (Details) - USD ($) $ / shares in Units, $ in Millions				3 Months Ended		6 Months Ended
	Apr. 26, 2016	Mar. 22, 2016	Jan. 27, 2016	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Stockholders' Equity Note [Abstract]
Cash dividends declared per common stock (in dollars per share)	$ 0.1		$ 0.1	$ 0.1	$ 0.1	$ 0.2	$ 0.2
Common stock dividends paid		$ 38.1				$ 76.4