Supplementary Financial Information, Summary of Quarterly Results (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Aug. 31, 2015	May. 31, 2015	Feb. 28, 2015	Nov. 30, 2014	Aug. 31, 2014	May. 31, 2014	Feb. 28, 2014	Nov. 30, 2013	Aug. 31, 2015	Aug. 31, 2014	Aug. 31, 2013
Supplementary Financial Information [Abstract]
Net sales	$ 28,522	$ 28,795	$ 26,573	$ 19,554	$ 19,057	$ 19,401	$ 19,605	$ 18,329	$ 103,444	$ 76,392	$ 72,217
Gross Profit	7,265	7,481	6,882	5,296	5,327	5,440	5,650	5,152	26,924	21,569	21,119
Net Earnings attributable to Walgreens Boots Alliance, Inc.	$ 26	$ 1,302	$ 2,042	$ 850	$ (221)	$ 714	$ 716	$ 723	$ 4,220	$ 1,932	$ 2,548
Net Earnings attributable to Walgreens Boots Alliance, Inc. [Abstract]
Basic (in dollars per share)	$ 0.02	$ 1.19	$ 1.96	$ 0.90	$ (0.23)	$ 0.75	$ 0.75	$ 0.76	$ 4.05	$ 2.03	$ 2.69
Diluted (in dollars per share)	0.02	1.18	1.93	0.89	(0.23)	0.74	0.74	0.75	4.00	2.00	2.67
Cash Dividends Declared Per Common Share (in dollars per share)	$ 0.3600	$ 0.3375	$ 0.3375	$ 0.3375	$ 0.3375	$ 0.3150	$ 0.3150	$ 0.3150	$ 1.3725	$ 1.2825	$ 1.14