Accumulated Other Comprehensive Loss (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Jan. 31, 2015	Jan. 31, 2014		Jan. 31, 2013
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Net gain on derivative instruments	$ 3.5	$ 2.8
Net unrealized gain on available-for-sale securities	1.8	2.9
Defined benefit pension items	(7.7)	(13.1)
Foreign currency translation adjustments	1.8	1.7
Accumulated other comprehensive loss	(0.6)	(5.7)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	47.0	11.1
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Reclassification Adjustments and Tax	(1.7)	(0.2)
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Reclassification Adjustments and Tax	(18.3)	3.9
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss), before Reclassification and Tax	(80.7)	(2.0)
Other Comprehensive Income (Loss), before Reclassifications, before Tax	(53.7)	12.8	[1]
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax	(7.0)	(11.5)
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI for Write-down of Securities, before Tax	1.7	(1.2)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), before Tax	0.5	0.9
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Net of Tax	0	0
Pre-tax reclassifications from Accumulated other comprehensive (loss)	(4.8)	(11.8)	[1]
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax	(0.7)	1.1
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI for Write-down of Securities, Tax	(0.2)	0.3
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Tax	1.8	0.6
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	4.9	2.1
Other Comprehensive Income (Loss), Tax	5.8	4.1	[1]
Net gain (loss) on derivative instruments (net of tax effect of ($0.7), $1.1, and ($0.5))	39.3	0.7		(6.4)
Change in net unrealized gain (loss) on available-for-sale securities (net of tax effect of ($0.2), $0.3, and ($0.6))	(0.2)	(1.1)		2.0
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	16.0	(5.4)		6.1
Net change in cumulative foreign currency translation (loss) gain (net of tax effect of $4.9, $2.1, and $2.1)	(75.8)	0.1		(1.1)
Other comprehensive income (loss)	(52.7)	5.1		(11.6)
Net gain on derivative instruments	42.8	3.5		2.8
Net unrealized gain on available-for-sale securities	1.6	1.8		2.9
Defined benefit pension items	(23.7)	(7.7)		(13.1)
Foreign currency translation adjustments	(74.0)	1.8		1.7
Accumulated other comprehensive loss	$ (53.3)	$ (0.6)		$ (5.7)

[1] For comparability, the presentation of prior period balances were adjusted to align with current year presentation.