Retirement Benefits (Details) $ in Millions	3 Months Ended		9 Months Ended
	May 31, 2016 USD ($)	May 31, 2015 USD ($)	May 31, 2016 USD ($) PensionPlan	May 31, 2015 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Number of defined benefit pension plans | PensionPlan			2
Employer cash contributions to defined benefit pension plans			$ 71
Walgreen Profit Sharing Retirement Trust [Member]
Defined Contribution Plan Disclosure [Line Items]
Profit sharing provision expense	$ 58	$ 64	169	$ 118
Alliance Boots Retirement Savings Plan [Member]
Defined Contribution Plan Disclosure [Line Items]
Cost recognized in the consolidated condensed statements of earnings	33	57	102	57
Boots and Other Pension Plans [Member]
Components of net periodic benefit costs [Abstract]
Service costs	1	2	3	3
Interest costs	77	79	236	132
Expected returns on plan assets	(62)	(65)	(189)	(108)
Settlements	0	(2)	0	(1)
Total net periodic pension costs	16	14	50	26
Postretirement Health Benefit Plan[Member]
Components of net periodic benefit costs [Abstract]
Service costs	3	3	8	8
Interest costs	4	5	14	13
Amortization of actuarial loss	5	4	14	14
Amortization of prior service cost	(7)	(6)	(21)	(18)
Total net periodic pension costs	$ 5	$ 6	$ 15	$ 17