Fair Value of Financial Instruments - Financial Assets and Liabilities Carried at Fair Value (Details) - USD ($) $ in Millions	Jan. 31, 2019	Jan. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets, fair value	$ 106.9	$ 347.7
Total financial liabilities, fair value	27.4	28.3
Other assets, net | Bank Time Deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets, fair value	62.7
Other assets, net | Marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets, fair value		22.5
Short-term Investments | Bank Time Deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets, fair value		320.5
Short-term Investments | Marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets, fair value	36.3
Prepaid expenses and other current assets | Cash Flow Hedging | Precious Metal Forward Contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value	5.2	3.6
Prepaid expenses and other current assets | Cash Flow Hedging | Foreign Exchange Forward
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value	1.8	0.1
Prepaid expenses and other current assets | Not Designated as Hedging Instrument | Foreign Exchange Forward
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value	0.9	1.0
Accounts Payable and Accrued Liabilities | Cash Flow Hedging | Precious Metal Forward Contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, fair value	2.7	1.9
Accounts Payable and Accrued Liabilities | Cash Flow Hedging | Foreign Exchange Forward
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, fair value	2.1	4.8
Accounts Payable and Accrued Liabilities | Cash Flow Hedging | Currency Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, fair value	19.9	20.2
Accounts Payable and Accrued Liabilities | Not Designated as Hedging Instrument | Foreign Exchange Forward
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, fair value	2.7	1.4
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets, fair value	99.0	343.0
Total financial liabilities, fair value	0.0	0.0
Level 1 | Other assets, net | Bank Time Deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets, fair value	62.7
Level 1 | Other assets, net | Marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets, fair value		22.5
Level 1 | Short-term Investments | Bank Time Deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets, fair value		320.5
Level 1 | Short-term Investments | Marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets, fair value	36.3
Level 1 | Prepaid expenses and other current assets | Cash Flow Hedging | Precious Metal Forward Contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value	0.0	0.0
Level 1 | Prepaid expenses and other current assets | Cash Flow Hedging | Foreign Exchange Forward
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value	0.0	0.0
Level 1 | Prepaid expenses and other current assets | Not Designated as Hedging Instrument | Foreign Exchange Forward
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value	0.0	0.0
Level 1 | Accounts Payable and Accrued Liabilities | Cash Flow Hedging | Precious Metal Forward Contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, fair value	0.0	0.0
Level 1 | Accounts Payable and Accrued Liabilities | Cash Flow Hedging | Foreign Exchange Forward
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, fair value	0.0	0.0
Level 1 | Accounts Payable and Accrued Liabilities | Cash Flow Hedging | Currency Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, fair value	0.0	0.0
Level 1 | Accounts Payable and Accrued Liabilities | Not Designated as Hedging Instrument | Foreign Exchange Forward
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, fair value	0.0	0.0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets, fair value	7.9	4.7
Total financial liabilities, fair value	27.4	28.3
Level 2 | Other assets, net | Bank Time Deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets, fair value	0.0
Level 2 | Other assets, net | Marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets, fair value		0.0
Level 2 | Short-term Investments | Bank Time Deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets, fair value		0.0
Level 2 | Short-term Investments | Marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets, fair value	0.0
Level 2 | Prepaid expenses and other current assets | Cash Flow Hedging | Precious Metal Forward Contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value	5.2	3.6
Level 2 | Prepaid expenses and other current assets | Cash Flow Hedging | Foreign Exchange Forward
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value	1.8	0.1
Level 2 | Prepaid expenses and other current assets | Not Designated as Hedging Instrument | Foreign Exchange Forward
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value	0.9	1.0
Level 2 | Accounts Payable and Accrued Liabilities | Cash Flow Hedging | Precious Metal Forward Contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, fair value	2.7	1.9
Level 2 | Accounts Payable and Accrued Liabilities | Cash Flow Hedging | Foreign Exchange Forward
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, fair value	2.1	4.8
Level 2 | Accounts Payable and Accrued Liabilities | Cash Flow Hedging | Currency Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, fair value	19.9	20.2
Level 2 | Accounts Payable and Accrued Liabilities | Not Designated as Hedging Instrument | Foreign Exchange Forward
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, fair value	2.7	1.4
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets, fair value	0.0	0.0
Total financial liabilities, fair value	0.0	0.0
Level 3 | Other assets, net | Bank Time Deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets, fair value	0.0
Level 3 | Other assets, net | Marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets, fair value		0.0
Level 3 | Short-term Investments | Bank Time Deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets, fair value		0.0
Level 3 | Short-term Investments | Marketable securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets, fair value	0.0
Level 3 | Prepaid expenses and other current assets | Cash Flow Hedging | Precious Metal Forward Contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value	0.0	0.0
Level 3 | Prepaid expenses and other current assets | Cash Flow Hedging | Foreign Exchange Forward
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value	0.0	0.0
Level 3 | Prepaid expenses and other current assets | Not Designated as Hedging Instrument | Foreign Exchange Forward
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, fair value	0.0	0.0
Level 3 | Accounts Payable and Accrued Liabilities | Cash Flow Hedging | Precious Metal Forward Contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, fair value	0.0	0.0
Level 3 | Accounts Payable and Accrued Liabilities | Cash Flow Hedging | Foreign Exchange Forward
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, fair value	0.0	0.0
Level 3 | Accounts Payable and Accrued Liabilities | Cash Flow Hedging | Currency Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, fair value	0.0	0.0
Level 3 | Accounts Payable and Accrued Liabilities | Not Designated as Hedging Instrument | Foreign Exchange Forward
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, fair value	$ 0.0	$ 0.0