Consolidated Statements of Comprehensive Income (Unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Aug. 31, 2017	Aug. 31, 2016	Aug. 31, 2017	Aug. 31, 2016
Statement of Comprehensive Income [Abstract]
Changes in instrument specific credit risk, tax expense (benefit)	$ 2.1	$ (1.6)	$ (5.3)	$ (3.1)