Valuation Techniques, Significant Unobservable Inputs, and Quantitative Information (Detail) - Jun. 30, 2015 - Fair Value, Measurements, Recurring - Fair Value, Inputs, Level 3 - USD ($) $ in Millions	Total
Swap Related to Sale of Certain Visa Class B Common Shares
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instrument, fair value liabilities	$ 11.3
Swap Related to Sale of Certain Visa Class B Common Shares | Group One
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Valuation Technique	Discounted Cash Flow
Unobservable Inputs	Visa Class A Appreciation
Swap Related to Sale of Certain Visa Class B Common Shares | Group Two
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Valuation Technique	Discounted Cash Flow
Unobservable Inputs	Conversion Rate
Swap Related to Sale of Certain Visa Class B Common Shares | Group Three
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Valuation Technique	Discounted Cash Flow
Unobservable Inputs	Expected Conversion Rate
Swap Related to Sale of Certain Visa Class B Common Shares | Lower Limit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instrument Visa Class A Appreciation	10.00%
Financial instrument Conversion Rate	1.61%
Financial instrument Expected Conversion Rate	2 years
Swap Related to Sale of Certain Visa Class B Common Shares | Upper Limit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instrument Visa Class A Appreciation	15.00%
Financial instrument Conversion Rate	1.65%
Financial instrument Expected Conversion Rate	5 years
Auction Rate Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Instrument, fair value assets	$ 16.6
Auction Rate Securities | Group One
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Valuation Technique	Discounted Cash Flow
Unobservable Inputs	Remaining lives
Auction Rate Securities | Group Two
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Valuation Technique	Discounted Cash Flow
Unobservable Inputs	Discount rates
Auction Rate Securities | Lower Limit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instrument remaining lives	10 months 24 days
Financial instrument discount rate	0.10%
Auction Rate Securities | Upper Limit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instrument remaining lives	8 years 7 months 6 days
Financial instrument discount rate	8.10%