Accumulated Other Comprehensive Income - Changes in AOCI (Detail) - USD ($) $ in Millions	12 Months Ended
	May 31, 2018	May 31, 2017	May 31, 2016
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ 12,407	$ 12,258	$ 12,707
Other comprehensive income (loss):
Other comprehensive gains (losses) before reclassifications, net of tax	(56)	119
Reclassifications to net income of previously deferred (gains) losses, net of tax	160	(650)
Total other comprehensive income (loss), net of tax	104	(531)	(928)
Reclassifications to retained earnings in accordance with ASU 2018-02(4)	17
Ending balance	9,812	12,407	12,258
Other comprehensive income, before reclassification, tax benefit (expense)	(31)	27
Reclassification from AOCI, current period, tax expense (benefit)	(3)	(6)
Foreign Currency Translation Adjustment
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(191)	(207)
Other comprehensive income (loss):
Other comprehensive gains (losses) before reclassifications, net of tax	(6)	15
Reclassifications to net income of previously deferred (gains) losses, net of tax	0	1
Total other comprehensive income (loss), net of tax	(6)	16
Reclassifications to retained earnings in accordance with ASU 2018-02(4)	24
Ending balance	(173)	(191)	(207)
Other comprehensive income, before reclassification, tax benefit (expense)	(24)	0
Reclassification from AOCI, current period, tax expense (benefit)	0	0
Cash Flow Hedges
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(52)	463
Other comprehensive income (loss):
Other comprehensive gains (losses) before reclassifications, net of tax	(52)	118
Reclassifications to net income of previously deferred (gains) losses, net of tax	128	(633)
Total other comprehensive income (loss), net of tax	76	(515)
Reclassifications to retained earnings in accordance with ASU 2018-02(4)	(7)
Ending balance	17	(52)	463
Other comprehensive income, before reclassification, tax benefit (expense)	(3)	24
Reclassification from AOCI, current period, tax expense (benefit)	(3)	(3)
Net Investment Hedges
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	115	115
Other comprehensive income (loss):
Other comprehensive gains (losses) before reclassifications, net of tax	0	0
Reclassifications to net income of previously deferred (gains) losses, net of tax	0	0
Total other comprehensive income (loss), net of tax	0	0
Reclassifications to retained earnings in accordance with ASU 2018-02(4)	0
Ending balance	115	115	115
Other comprehensive income, before reclassification, tax benefit (expense)	0	0
Reclassification from AOCI, current period, tax expense (benefit)	0	0
Other
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(85)	(53)
Other comprehensive income (loss):
Other comprehensive gains (losses) before reclassifications, net of tax	2	(14)
Reclassifications to net income of previously deferred (gains) losses, net of tax	32	(18)
Total other comprehensive income (loss), net of tax	34	(32)
Reclassifications to retained earnings in accordance with ASU 2018-02(4)	0
Ending balance	(51)	(85)	(53)
Other comprehensive income, before reclassification, tax benefit (expense)	(4)	3
Reclassification from AOCI, current period, tax expense (benefit)	0	(3)
Total
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(213)	318
Other comprehensive income (loss):
Ending balance	$ (92)	$ (213)	$ 318