Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Feb. 29, 2016	Feb. 28, 2015	Feb. 29, 2016	Feb. 28, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ (658)	$ 54	$ (214)	$ 136
Other comprehensive income (loss) before reclassification adjustments	(1,264)	(313)	(1,715)	(436)
Amounts reclassified from accumulated OCI	2	309	3	309
Tax benefit (provision)	52	(118)	58	(77)
Net other comprehensive income (loss)	(1,210)	(122)	(1,654)	(204)
Ending Balance	(1,868)	(68)	(1,868)	(68)
Pension/Post-retirement Obligations [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	32	14	29	15
Other comprehensive income (loss) before reclassification adjustments	(4)	(8)	(1)	(10)
Amounts reclassified from accumulated OCI	0	0	0	0
Tax benefit (provision)	2	0	2	1
Net other comprehensive income (loss)	(2)	(8)	1	(9)
Ending Balance	30	6	30	6
Unrecognized Gain (Loss) on Available-for-Sale Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	260	206	259	107
Other comprehensive income (loss) before reclassification adjustments	(139)	140	(144)	297
Amounts reclassified from accumulated OCI	0	0	0	0
Tax benefit (provision)	51	(50)	57	(108)
Net other comprehensive income (loss)	(88)	90	(87)	189
Ending Balance	172	296	172	296
Unrealized Gain (Loss) on Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(39)	(39)	(40)	(27)
Other comprehensive income (loss) before reclassification adjustments	0	2	0	(18)
Amounts reclassified from accumulated OCI	2	(1)	3	(1)
Tax benefit (provision)	(1)	(1)	(1)	7
Net other comprehensive income (loss)	1	0	2	(12)
Ending Balance	(38)	(39)	(38)	(39)
Share of Alliance Boots OCI [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(92)		(113)
Other comprehensive income (loss) before reclassification adjustments		(89)		(57)
Amounts reclassified from accumulated OCI		230		230
Tax benefit (provision)		(49)		(60)
Net other comprehensive income (loss)		92		113
Ending Balance		0		0
Cumulative Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(911)	(35)	(462)	154
Other comprehensive income (loss) before reclassification adjustments	(1,121)	(358)	(1,570)	(648)
Amounts reclassified from accumulated OCI	0	80	0	80
Tax benefit (provision)	0	(18)	0	83
Net other comprehensive income (loss)	(1,121)	(296)	(1,570)	(485)
Ending Balance	$ (2,032)	$ (331)	$ (2,032)	$ (331)