Retirement Benefits (Details) $ in Millions	3 Months Ended		6 Months Ended
	Feb. 29, 2016 USD ($)	Feb. 28, 2015 USD ($)	Feb. 29, 2016 USD ($) PensionPlan	Feb. 28, 2015 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Number of defined benefit pension plans | PensionPlan			2
Employer cash contributions to defined benefit pension plans			$ 9
Employee expected additional contribution in current fiscal year			66
Walgreen Profit Sharing Retirement Trust [Member]
Defined Contribution Plan Disclosure [Line Items]
Profit sharing provision expense	$ 53	$ 21	111	$ 54
Alliance Boots Retirement Savings Plan [Member]
Defined Contribution Plan Disclosure [Line Items]
Cost recognized in the consolidated condensed statements of earnings	34	22	69	22
Boots and Other Pension Plans [Member]
Components of net periodic benefit costs [Abstract]
Service costs	0	1	2	1
Interest costs	77	53	159	53
Expected returns on plan assets	(62)	(43)	(127)	(43)
Settlements	0	1	0	1
Total net periodic pension costs	15	12	34	12
Postretirement Health Benefit Plan[Member]
Components of net periodic benefit costs [Abstract]
Service costs	2	2	5	5
Interest costs	5	4	10	8
Amortization of actuarial loss	5	5	9	10
Amortization of prior service cost	(7)	(6)	(14)	(12)
Total net periodic pension costs	$ 5	$ 5	$ 10	$ 11