Supplemental Guarantor Condensed Consolidating Financial Information, Statements of Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	May. 31, 2015	May. 31, 2014	May. 31, 2015	May. 31, 2014
Statement of Comprehensive Income [Abstract]
Net Earnings (loss)	$ 1,310	$ 756	$ 4,247	$ 2,218
Other comprehensive income (loss), net of tax [Abstract]
Postretirement liability	(2)	(2)	(11)	4
Unrealized gain (loss) on cash flow hedges	0	(13)	(12)	(13)
Changes in unrecognized gain (loss) on available-for-sale investments	74	40	263	75
Share of other comprehensive income (loss) of Alliance Boots	0	49	113	(7)
Currency translation adjustments	(149)	24	(639)	305
Other Comprehensive Income (loss) of subsidiaries	0	0	0	0
Total Other Comprehensive Income (Loss)	(77)	98	(286)	364
Total Comprehensive Income	1,233	854	3,961	2,582
Comprehensive income attributable to noncontrolling interests	4	42	44	65
Comprehensive Income Attributable to Walgreens Boots Alliance, Inc.	1,229	812	3,917	2,517
Guarantor Subsidiary [Member]
Statement of Comprehensive Income [Abstract]
Net Earnings (loss)	782	756	2,381	2,218
Other comprehensive income (loss), net of tax [Abstract]
Postretirement liability	0	(2)	(2)	4
Unrealized gain (loss) on cash flow hedges	0	(13)	(11)	(13)
Changes in unrecognized gain (loss) on available-for-sale investments	0	0	0	0
Share of other comprehensive income (loss) of Alliance Boots	0	0	0	0
Currency translation adjustments	0	0	0	0
Other Comprehensive Income (loss) of subsidiaries	(77)	113	(273)	373
Total Other Comprehensive Income (Loss)	(77)	98	(286)	364
Total Comprehensive Income	705	854	2,095	2,582
Comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive Income Attributable to Walgreens Boots Alliance, Inc.	705	854	2,095	2,582
Non-guarantor Subsidiaries [Member]
Statement of Comprehensive Income [Abstract]
Net Earnings (loss)	726	177	3,711	1,229
Other comprehensive income (loss), net of tax [Abstract]
Postretirement liability	(2)	0	(9)	0
Unrealized gain (loss) on cash flow hedges	0	0	(1)	0
Changes in unrecognized gain (loss) on available-for-sale investments	74	40	263	75
Share of other comprehensive income (loss) of Alliance Boots	0	49	113	(7)
Currency translation adjustments	(149)	24	(639)	305
Other Comprehensive Income (loss) of subsidiaries	0	0	0	0
Total Other Comprehensive Income (Loss)	(77)	113	(273)	373
Total Comprehensive Income	649	290	3,438	1,602
Comprehensive income attributable to noncontrolling interests	4	42	44	65
Comprehensive Income Attributable to Walgreens Boots Alliance, Inc.	645	248	3,394	1,537
Parent Company [Member]
Statement of Comprehensive Income [Abstract]
Net Earnings (loss)	1,310	0	4,247	0
Other comprehensive income (loss), net of tax [Abstract]
Postretirement liability	0	0	0	0
Unrealized gain (loss) on cash flow hedges	0	0	0	0
Changes in unrecognized gain (loss) on available-for-sale investments	0	0	0	0
Share of other comprehensive income (loss) of Alliance Boots	0	0	0	0
Currency translation adjustments	0	0	0	0
Other Comprehensive Income (loss) of subsidiaries	(77)	0	(286)	0
Total Other Comprehensive Income (Loss)	(77)	0	(286)	0
Total Comprehensive Income	1,233	0	3,961	0
Comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive Income Attributable to Walgreens Boots Alliance, Inc.	1,233	0	3,961	0
Consolidating Adjustments [Member]
Statement of Comprehensive Income [Abstract]
Net Earnings (loss)	(1,508)	(177)	(6,092)	(1,229)
Other comprehensive income (loss), net of tax [Abstract]
Postretirement liability	0	0	0	0
Unrealized gain (loss) on cash flow hedges	0	0	0	0
Changes in unrecognized gain (loss) on available-for-sale investments	0	0	0	0
Share of other comprehensive income (loss) of Alliance Boots	0	0	0	0
Currency translation adjustments	0	0	0	0
Other Comprehensive Income (loss) of subsidiaries	154	(113)	559	(373)
Total Other Comprehensive Income (Loss)	154	(113)	559	(373)
Total Comprehensive Income	(1,354)	(290)	(5,533)	(1,602)
Comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive Income Attributable to Walgreens Boots Alliance, Inc.	$ (1,354)	$ (290)	$ (5,533)	$ (1,602)