Common and Preferred Stock Accelerated Share Repurchase (Details) - USD ($) shares in Millions, $ in Millions			12 Months Ended
	May 21, 2015	Jun. 20, 2014	Dec. 31, 2015
Accelerated Share Repurchase [Abstract]
Accelerated Share Repurchase Program Repurchase Amount	$ 100.0	$ 200.0
Shares received under accelerated share repurchase program			7.9