Equity - Capital Purchase Program Warrants (Details) - $ / shares shares in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Class of Warrant or Right [Line Items]
Warrants outstanding	2.1	2.1		2.2
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 8.930	$ 8.930		$ 8.999
Warrant [Member]
Class of Warrant or Right [Line Items]
Warrants Exercised	0.1	0.1	1.1