Borrowings, Long-Term Debt (Details) - USD ($) $ in Millions		12 Months Ended
		Aug. 31, 2016	Aug. 31, 2015
Long-Term Debt [Abstract]
Other	[1],[2]	$ 32	$ 44
Total long-term debt	[1]	18,705	13,315
Unsecured Pound Sterling Variable Rate Term Loan Due 2019 [Member]
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	[1],[3]	$ 1,833	2,229
Maturity year	[1],[3]	2019
1.750% unsecured notes due 2018 [Member]
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	[1],[4],[5]	$ 1,246	0
Stated interest rate	[1],[4],[5]	1.75%
Maturity year	[1],[4],[5]	2018
2.600% unsecured notes due 2021 [Member]
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	[1],[4],[5],[6]	$ 1,493	0
Stated interest rate	[1],[4],[5],[6]	2.60%
Maturity year	[1],[4],[5],[6]	2021
3.100% unsecured notes due 2023 [Member]
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	[1],[4],[5],[6]	$ 744	0
Stated interest rate	[1],[4],[5],[6]	3.10%
Maturity year	[1],[4],[5],[6]	2023
3.450% unsecured notes due 2026 [Member]
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	[1],[3],[4],[5]	$ 1,885	0
Stated interest rate	[1],[3],[4],[5]	3.45%
Maturity year	[1],[3],[4],[5]	2026
4.650% unsecured notes due 2046 [Member]
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	[1],[3],[4],[5]	$ 590	0
Stated interest rate	[1],[3],[4],[5]	4.65%
Maturity year	[1],[3],[4],[5]	2046
1.750% Unsecured Notes due 2017 [Member]
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	[1],[4],[5]	$ 746	746
Stated interest rate	[1],[4],[5]	1.75%
Maturity year	[1],[4],[5]	2017
2.700% Unsecured Notes Due 2019 [Member]
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	[1],[4],[5]	$ 1,244	1,243
Stated interest rate	[1],[4],[5]	2.70%
Maturity year	[1],[4],[5]	2019
3.300% Unsecured Notes Due 2021 [Member]
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	[1],[4],[5]	$ 1,242	1,241
Stated interest rate	[1],[4],[5]	3.30%
Maturity year	[1],[4],[5]	2021
3.800% Unsecured Notes Due 2024 [Member]
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	[1],[3],[4],[5]	$ 1,987	1,985
Stated interest rate	[1],[3],[4],[5]	3.80%
Maturity year	[1],[3],[4],[5]	2024
4.500% Unsecured Notes Due 2034 [Member]
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	[1],[3],[4],[5]	$ 494	494
Stated interest rate	[1],[3],[4],[5]	4.50%
Maturity year	[1],[3],[4],[5]	2034
4.800% Unsecured Notes Due 2044 [Member]
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	[1],[4],[5],[7]	$ 1,492	1,491
Stated interest rate	[1],[4],[5],[7]	4.80%
Maturity year	[1],[4],[5],[7]	2044
2.875% Unsecured Pound Sterling Notes Due 2020 [Member]
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	[1],[4],[5],[6]	$ 521	612
Stated interest rate	[1],[4],[5],[6]	2.875%
Maturity year	[1],[4],[5],[6]	2020
3.600% Unsecured Pound Sterling Notes Due 2025 [Member]
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	[1],[4],[5],[6]	$ 391	459
Stated interest rate	[1],[4],[5],[6]	3.60%
Maturity year	[1],[4],[5],[6]	2025
2.125% Unsecured Euro Notes Due 2026 [Member]
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	[1],[4],[5],[7]	$ 830	836
Stated interest rate	[1],[4],[5],[7]	2.125%
Maturity year	[1],[4],[5],[7]	2026
3.100% Unsecured Notes Due 2022 [Member]
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	[1],[4],[5],[8]	$ 1,194	1,193
Stated interest rate	[1],[4],[5],[8]	3.10%
Maturity year	[1],[4],[5],[8]	2022
4.400% Unsecured Notes Due 2042 [Member]
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	[1],[4],[5],[8]	$ 492	492
Stated interest rate	[1],[4],[5],[8]	4.40%
Maturity year	[1],[4],[5],[8]	2042
5.250% Unsecured Notes Due 2019 [Member]
Long-Term Debt [Abstract]
Carrying value of notes, net of unamortized discount and interest rate swap FMV adjustment	[1],[4],[8]	$ 249	$ 250
Stated interest rate	[1],[4],[8]	5.25%
Maturity year	[1],[4],[8]	2019

[1] All notes are presented net of unamortized discount and debt issuance costs, where applicable.

[2] Other long-term debt represents a mix of fixed and variable rate borrowings in various foreign currencies with various maturities.

[3] Includes interest rate swap fair market value adjustments. See Note 11, Fair Value Measurements for additional fair value disclosures.

[4] The fair value of the $6 billion, $8 billion, £0.7 billion, €0.75 billion, $4 billion and $1 billion note issuances as of August 31, 2016 was $6.2 billion, $7.7 billion, $1.0 billion, $0.9 billion, $1.8 billion and $0.3 billion, respectively. The fair values of the notes outstanding are Level 1 fair value measures and determined based on quoted market price and translated at the August 31, 2016 spot rate, as applicable.

[5] Notes are unsubordinated debt obligations of Walgreens Boots Alliance and rank equally in right of payment with all other unsecured and unsubordinated indebtedness of Walgreens Boots Alliance from time to time outstanding.

[6] Pound Sterling denominated notes are translated at the spot rates at August 31, 2016 and 2015, respectively.

[7] Euro denominated notes are translated at the spot rate at August 31, 2016 and 2015.

[8] Notes are senior debt obligations of Walgreens and rank equally with all other unsecured and unsubordinated indebtedness of Walgreens. On December 31, 2014, Walgreens Boots Alliance fully and unconditionally guaranteed the outstanding notes on an unsecured and unsubordinated basis. The guarantee, for so long as it is in place, is an unsecured, unsubordinated debt obligation of Walgreens Boots Alliance and will rank equally in right of payment with all other unsecured and unsubordinated indebtedness of Walgreens Boots Alliance.