Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	12 Months Ended
	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ 2,219.2	$ 2,261.5	$ 2,043.2
Total other comprehensive (loss) income	(67.8)	(52.7)	5.1
Ending Balance	1,619.6	2,219.2	2,261.5
Accumulated other comprehensive (loss) income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(53.3)	(0.6)	(5.7)
Other comprehensive income (loss) before reclassifications	(41.7)	(53.7)
Pre-tax (gains) losses reclassified from accumulated other comprehensive income	(28.1)	(4.8)
Tax effects	2.0	5.8
Total other comprehensive (loss) income	(67.8)	(52.7)
Ending Balance	(121.1)	(53.3)	(0.6)
Net Unrealized Gains (Losses) on Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	42.8	3.5
Other comprehensive income (loss) before reclassifications	1.6	47.0
Pre-tax (gains) losses reclassified from accumulated other comprehensive income	(29.3)	(7.0)
Tax effects	0.6	(0.7)
Total other comprehensive (loss) income	(27.1)	39.3
Ending Balance	15.7	42.8	3.5
Net Unrealized Gains (Losses) on Available for Sale Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	1.6	1.8
Other comprehensive income (loss) before reclassifications	(1.3)	(1.7)
Pre-tax (gains) losses reclassified from accumulated other comprehensive income	(0.1)	1.7
Tax effects	0.0	(0.2)
Total other comprehensive (loss) income	(1.4)	(0.2)
Ending Balance	0.2	1.6	1.8
Defined Benefit Pension Components
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(23.7)	(7.7)
Other comprehensive income (loss) before reclassifications	(6.8)	(18.3)
Pre-tax (gains) losses reclassified from accumulated other comprehensive income	1.3	0.5
Tax effects	0.9	1.8
Total other comprehensive (loss) income	(4.6)	(16.0)
Ending Balance	(28.3)	(23.7)	(7.7)
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(74.0)	1.8
Other comprehensive income (loss) before reclassifications	(35.2)	(80.7)
Pre-tax (gains) losses reclassified from accumulated other comprehensive income	0.0	0.0
Tax effects	0.5	4.9
Total other comprehensive (loss) income	(34.7)	(75.8)
Ending Balance	$ (108.7)	$ (74.0)	$ 1.8