Retirement Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Feb. 28, 2015	Feb. 28, 2014	Feb. 28, 2015	Feb. 28, 2014
Defined Benefit Plan Disclosure [Line Items]
Number of defined benefit pension plans			3
Employer cash contributions to defined benefit pension plans			$ 85
Employee expected additional contribution in current fiscal year			65
Walgreen Profit Sharing Retirement Trust [Member]
Defined Contribution Plan Disclosure [Line Items]
Profit sharing provision (benefit) expense	21	85	54	165
Alliance Boots Retirement Savings Plan [Member]
Defined Contribution Plan Disclosure [Line Items]
Cost recognized in the consolidated condensed statements of earnings			22
Boots Pension Plan [Member]
Components of net periodic benefit costs [Abstract]
Service cost	0		0
Interest cost	52		52
Expected return on plan assets	(43)		(43)
Settlements	0		0
Total postretirement benefit cost	9		9
Other Pension Plan [Member]
Components of net periodic benefit costs [Abstract]
Service cost	1		1
Interest cost	1		1
Expected return on plan assets	0		0
Settlements	1		1
Total postretirement benefit cost	3		3
Postretirement Health Benefit Plan[Member]
Components of net periodic benefit costs [Abstract]
Service cost	2	2	5	4
Interest cost	4	4	8	8
Amortization of actuarial loss	5	3	10	6
Amortization of prior service cost	(6)	(6)	(12)	(11)
Total postretirement benefit cost	$ 5	$ 3	$ 11	$ 7