Accumulated Other Comprehensive Income - Changes in AOCI (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Feb. 28, 2015		Feb. 28, 2014		Feb. 28, 2015		Feb. 28, 2014
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accumulated other comprehensive income balance at the beginning of the period	$ 525		$ 90		$ 85		$ 274
Other comprehensive gains (losses) before reclassifications, net of tax	691	[1]	(68)	[2]	1,143	[3]	(209)	[4]
Reclassifications to net income of previously deferred (gains) losses, net of tax	(105)	[5]	11	[6]	(117)	[7]	(32)	[8]
Other comprehensive income (loss)	586		(57)		1,026		(241)
Accumulated other comprehensive income balance at the end of the period	1,111		33		1,111		33
Other comprehensive income, before reclassification, tax benefit (expense)	(69)		5		(99)		12
Reclassification from accumulated other comprehensive income, tax (benefit) expense	(11)		1		(7)		(9)
Foreign Currency Translation Adjustment
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accumulated other comprehensive income balance at the beginning of the period	(23)	[9]	24	[9]	9	[9]	41	[9]
Other comprehensive gains (losses) before reclassifications, net of tax	15	[1],[9]	(34)	[2],[9]	(17)	[3],[9]	(51)	[4],[9]
Reclassifications to net income of previously deferred (gains) losses, net of tax	0	[5],[9]	0	[6],[9]	0	[7],[9]	0	[8],[9]
Other comprehensive income (loss)	15	[9]	(34)	[9]	(17)	[9]	(51)	[9]
Accumulated other comprehensive income balance at the end of the period	(8)	[9]	(10)	[9]	(8)	[9]	(10)	[9]
Other comprehensive income, before reclassification, tax benefit (expense)	(3)		0		(3)		0
Reclassification from accumulated other comprehensive income, tax (benefit) expense	0		0		0		0
Cash Flow Hedges
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accumulated other comprehensive income balance at the beginning of the period	500		28		32		193
Other comprehensive gains (losses) before reclassifications, net of tax	661	[1]	(31)	[2]	1,131	[3]	(151)	[4]
Reclassifications to net income of previously deferred (gains) losses, net of tax	(92)	[5]	10	[6]	(94)	[7]	(35)	[8]
Other comprehensive income (loss)	569		(21)		1,037		(186)
Accumulated other comprehensive income balance at the end of the period	1,069		7		1,069		7
Other comprehensive income, before reclassification, tax benefit (expense)	(61)		5		(88)		12
Reclassification from accumulated other comprehensive income, tax (benefit) expense	(7)		1		0		(9)
Net Investment Hedges
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accumulated other comprehensive income balance at the beginning of the period	95	[9]	95	[9]	95	[9]	95	[9]
Other comprehensive gains (losses) before reclassifications, net of tax	0	[1],[9]	0	[2],[9]	0	[3],[9]	0	[4],[9]
Reclassifications to net income of previously deferred (gains) losses, net of tax	0	[5],[9]	0	[6],[9]	0	[7],[9]	0	[8],[9]
Other comprehensive income (loss)	0	[9]	0	[9]	0	[9]	0	[9]
Accumulated other comprehensive income balance at the end of the period	95	[9]	95	[9]	95	[9]	95	[9]
Other comprehensive income, before reclassification, tax benefit (expense)	0		0		0		0
Reclassification from accumulated other comprehensive income, tax (benefit) expense	0		0		0		0
Other
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accumulated other comprehensive income balance at the beginning of the period	(47)		(57)		(51)		(55)
Other comprehensive gains (losses) before reclassifications, net of tax	15	[1]	(3)	[2]	29	[3]	(7)	[4]
Reclassifications to net income of previously deferred (gains) losses, net of tax	(13)	[5]	1	[6]	(23)	[7]	3	[8]
Other comprehensive income (loss)	2		(2)		6		(4)
Accumulated other comprehensive income balance at the end of the period	(45)		(59)		(45)		(59)
Other comprehensive income, before reclassification, tax benefit (expense)	(5)		0		(8)		0
Reclassification from accumulated other comprehensive income, tax (benefit) expense	$ (4)		$ 0		$ (7)		$ 0

[1] Net of tax benefit (expense) of $(3) million, $(61) million, $0 million, $(5) million and $(69) million, respectively.

[2] Net of tax benefit (expense) of $0 million, $5 million, $0 million, $0 million and $5 million, respectively.

[3] Net of tax benefit (expense) of $(3) million, $(88) million, $0 million, $(8) million and $(99) million, respectively.

[4] Net of tax benefit (expense) of $0 million, $12 million, $0 million, $0 million and $12 million, respectively.

[5] Net of tax (benefit) expense of $0 million, $7 million, $0 million, $4 million and $11 million, respectively.

[6] Net of tax (benefit) expense of $0 million, $(1) million, $0 million, $0 million and $(1) million, respectively.

[7] Net of tax (benefit) expense of $0 million, $0 million, $0 million, $7 million and $7 million, respectively.

[8] Net of tax (benefit) expense of $0 million, $9 million, $0 million, $0 million and $9 million, respectively.

[9] The accumulated foreign currency translation adjustment and net investment hedge gains/losses related to an investment in a foreign subsidiary are reclassified to Net income upon sale or upon complete or substantially complete liquidation of the respective entity.