Subsequent Events (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended				12 Months Ended			0 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Feb. 20, 2015
Subsequent events
Cash dividends declared per common share	$ 0.25	$ 0.25	$ 0	$ 0	$ 0.50	$ 0.00	$ 0.00
Subsequent events
Subsequent events
Cash dividends declared per common share								$ 0.25
Dividends Payable								$ 29.2