Retirement Benefits - Components of Retirement Benefit Expense (Income) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Aug. 31, 2014	Aug. 31, 2013	Aug. 31, 2014	Aug. 31, 2013
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2.2	$ 1.7	$ 6.6	$ 4.4
Interest cost on benefit obligation	16.8	15.3	50.3	45.7
Assumed return on plan assets	(23.3)	(24.1)	(69.7)	(72.3)
Amortization of prior service credits	0	0	0	0
Recognized net actuarial losses (gains)	13.5	23.7	40.4	71.0
Retirement benefit expense (income)	9.2	16.6	27.6	48.8
Postretirement Medical and Life Insurance Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0.1	0	0.1	0.1
Interest cost on benefit obligation	0.6	0.6	1.9	1.8
Assumed return on plan assets	0	0	0	0
Amortization of prior service credits	(0.2)	(0.2)	(0.6)	(0.6)
Recognized net actuarial losses (gains)	(0.8)	(0.5)	(2.3)	(1.6)
Retirement benefit expense (income)	$ (0.3)	$ (0.1)	$ (0.9)	$ (0.3)