Accumulated Other Comprehensive Income - Changes in AOCI (Detail) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
	Feb. 29, 2016		Feb. 28, 2015		Feb. 29, 2016		Feb. 28, 2015		Aug. 31, 2015	May. 31, 2015	Aug. 31, 2014	May. 31, 2014
AOCI Including Portion Attributable to Noncontrolling, Net of Tax [Roll Forward]
Accumulated other comprehensive income balance at the beginning of the period	$ 1,107		$ 525		$ 1,246		$ 85
Other comprehensive gains (losses) before reclassifications, net of tax	(261)	[1]	691	[2]	(77)	[3]	1,143	[4]
Reclassifications to net income of previously deferred (gains) losses, net of tax	(201)	[5]	(105)	[6]	(524)	[7]	(117)	[8]
Total other comprehensive income (loss), net of tax	(462)		586		(601)		1,026
Accumulated other comprehensive income balance at the end of the period	645		1,111		645		1,111
Other comprehensive income, before reclassification, tax benefit (expense)	23		(69)		37		(99)
Reclassification from accumulated other comprehensive income, tax (benefit) expense	3		11		4		7
Foreign Currency Translation Adjustment
AOCI Including Portion Attributable to Noncontrolling, Net of Tax [Roll Forward]
Accumulated other comprehensive income balance at the beginning of the period	(141)	[9]	(43)	[10],[11]	(31)	[12],[13]	(11)	[14],[15]
Other comprehensive gains (losses) before reclassifications, net of tax	(113)	[1],[9]	15	[2],[10],[11]	(223)	[3],[12],[13]	(17)	[4],[14],[15]
Reclassifications to net income of previously deferred (gains) losses, net of tax	2	[5],[9]	0	[6],[10],[11]	2	[7],[12],[13]	0	[8],[14],[15]
Total other comprehensive income (loss), net of tax	(111)	[9]	15	[10],[11]	(221)	[12],[13]	(17)	[14],[15]
Accumulated other comprehensive income balance at the end of the period	(252)	[9],[12],[13]	(28)	[10],[11],[14],[15]	(252)	[9],[12],[13]	(28)	[10],[11],[14],[15]
Other comprehensive income, before reclassification, tax benefit (expense)	0		(3)		0		(3)
Reclassification from accumulated other comprehensive income, tax (benefit) expense	0		0		0		0
Cash Flow Hedges
AOCI Including Portion Attributable to Noncontrolling, Net of Tax [Roll Forward]
Accumulated other comprehensive income balance at the beginning of the period	1,181		500		1,220		32
Other comprehensive gains (losses) before reclassifications, net of tax	(151)	[1]	661	[2]	132	[3]	1,131	[4]
Reclassifications to net income of previously deferred (gains) losses, net of tax	(199)	[5]	(92)	[6]	(521)	[7]	(94)	[8]
Total other comprehensive income (loss), net of tax	(350)		569		(389)		1,037
Accumulated other comprehensive income balance at the end of the period	831		1,069		831		1,069
Other comprehensive income, before reclassification, tax benefit (expense)	24		(61)		40		(88)
Reclassification from accumulated other comprehensive income, tax (benefit) expense	3		7		4		0
Net Investment Hedges
AOCI Including Portion Attributable to Noncontrolling, Net of Tax [Roll Forward]
Accumulated other comprehensive income balance at the beginning of the period	115	[9]	115	[10],[11]	115	[12],[13]	115	[14],[15]
Other comprehensive gains (losses) before reclassifications, net of tax	0	[1],[9]	0	[2],[10],[11]	0	[3],[12],[13]	0	[4],[14],[15]
Reclassifications to net income of previously deferred (gains) losses, net of tax	0	[5],[9]	0	[6],[10],[11]	0	[7],[12],[13]	0	[8],[14],[15]
Total other comprehensive income (loss), net of tax	0	[9]	0	[10],[11]	0	[12],[13]	0	[14],[15]
Accumulated other comprehensive income balance at the end of the period	115	[9],[12],[13]	115	[10],[11],[14],[15]	115	[9],[12],[13]	115	[10],[11],[14],[15]
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
AOCI Including Portion Attributable to Noncontrolling, Net of Tax [Roll Forward]
Accumulated other comprehensive income balance at the beginning of the period	(48)		(47)		(58)		(51)
Other comprehensive gains (losses) before reclassifications, net of tax	3	[1]	15	[2]	14	[3]	29	[4]
Reclassifications to net income of previously deferred (gains) losses, net of tax	(4)	[5]	(13)	[6]	(5)	[7]	(23)	[8]
Total other comprehensive income (loss), net of tax	(1)		2		9		6
Accumulated other comprehensive income balance at the end of the period	(49)		(45)		(49)		(45)
Other comprehensive income, before reclassification, tax benefit (expense)	(1)		(5)		(3)		(8)
Reclassification from accumulated other comprehensive income, tax (benefit) expense	$ 0		4		0		7
Revisions
AOCI Including Portion Attributable to Noncontrolling, Net of Tax [Roll Forward]
Accumulated other comprehensive income balance at the beginning of the period			$ 20		$ 20		$ 20
Translation adjustment for net investment hedge									$ 20	$ 20	$ 20	$ 20

[1] Net of tax benefit (expense) of $0 million, $24 million, $0 million, $(1) million and $23 million, respectively.

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

[3] Net of tax benefit (expense) of $0 million, $40 million, $0 million, $(3) million and $37 million, respectively.

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

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

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

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

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

[10] Beginning and ending balances have been updated to reflect the proper classification of $20 million of deferred tax balances between Foreign Currency Translation Adjustment and Net Investment Hedges.

[11] 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.

[12] Beginning balances have been updated to reflect the proper classification of $20 million of deferred tax balances between Foreign Currency Translation Adjustment and Net Investment Hedges.

[13] 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.

[14] Beginning and ending balances have been updated to reflect the proper classification of $20 million of deferred tax balances between Foreign Currency Translation Adjustment and Net Investment Hedges.

[15] 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.