Risk Management and Derivatives - Additional Information (Detail) - USD ($)		3 Months Ended		9 Months Ended
	Oct. 29, 2015	Feb. 29, 2016	Feb. 28, 2015	Feb. 29, 2016	Feb. 28, 2015	May. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Amount of Ineffectiveness on Net Investment Hedges		$ 0	$ 0	$ 0	$ 0
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net		$ 0	$ 0	$ 0	$ 0
Percentage of anticipated exposures hedged (percent)		100.00%		100.00%
Deferred net gains (net of tax) on both outstanding and matured derivatives accumulated in other comprehensive income are expected to be reclassified to net income during the next twelve months as a result of underlying hedged transactions also being recorded in net income		$ 693,000,000		$ 693,000,000
Maximum term over which the Company is hedging exposures to the variability of cash flows for its forecasted and recorded transactions (in months)				27 months
Collateral received from counterparties to hedging instruments		338,000,000		$ 338,000,000		$ 968,000,000
Embedded derivatives
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Total notional amount of outstanding derivatives		237,000,000		237,000,000
Undesignated derivative instruments
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Total notional amount of outstanding derivatives		5,700,000,000		$ 5,700,000,000
Minimum
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Typical time period that anticipated exposures are hedged against (in months)				12 months
Minimum fair value of outstanding derivative above which the credit related contingent features require the derivative party to post collateral		50,000,000		$ 50,000,000
Maximum
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Typical time period that anticipated exposures are hedged against (in months)				24 months
Derivatives designated as fair value hedges | Interest rate swap
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Total notional amount of outstanding derivatives		0		$ 0
Derivatives designated as cash flow hedges
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Total notional amount of outstanding derivatives		11,800,000,000		11,800,000,000
Derivatives designated as cash flow hedges | Derivatives formally designated as hedging instruments | Interest rate swap
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Total notional amount of outstanding derivatives		1,500,000,000.0		1,500,000,000.0
Derivative, Notional Amount, Terminated		1,000,000,000		1,000,000,000
Proceeds from termination of derivative	$ 34,000,000
Derivatives designated as net investment hedges | Foreign exchange forwards and options
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Derivative assets (liabilities), at fair value, net		0		0
Cash and Cash Equivalents
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Collateral received from counterparties to hedging instruments		338,000,000		338,000,000
Cash and Cash Equivalents | Interest rate swap
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Collateral received from counterparties to hedging instruments						68,000,000
Cash and Cash Equivalents | Foreign exchange forwards and options
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Collateral received from counterparties to hedging instruments		$ 338,000,000		$ 338,000,000		$ 900,000,000