Retirement Benefits (Details) $ in Millions	3 Months Ended
	Nov. 30, 2015 USD ($) PensionPlan	Nov. 30, 2014 USD ($)
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	58	$ 75
Alliance Boots Retirement Savings Plan [Member]
Defined Contribution Plan Disclosure [Line Items]
Cost recognized in the consolidated condensed statements of earnings	35
Boots and Other Pension Plans [Member]
Components of net periodic benefit costs [Abstract]
Service costs	1	0
Interest costs	81	0
Expected returns on plan assets	(65)	0
Total net periodic pension costs	17	0
Postretirement Health Benefit Plan[Member]
Components of net periodic benefit costs [Abstract]
Service costs	3	3
Interest costs	5	4
Amortization of actuarial loss	4	5
Amortization of prior service cost	(7)	(6)
Total net periodic pension costs	$ 5	$ 6