Financial Instruments (Details) $ / shares in Units, € in Millions, $ in Millions, £ in Billions		3 Months Ended			9 Months Ended
		May. 31, 2015 USD ($) $ / shares shares		May. 31, 2014 USD ($)	May. 31, 2015 USD ($) $ / shares shares		May. 31, 2014 USD ($)	May. 31, 2015 GBP (£) shares	May. 31, 2015 EUR (€) shares	Jan. 31, 2015 GBP (£)	Jan. 31, 2015 EUR (€)	Aug. 31, 2014 USD ($)
Effect of Fair Value Hedges on Results of Operations [Abstract]
Cumulative fair value adjustments resulted in increase in long-term debt		$ 25			$ 25							$ 12
Cash Flow Hedges [Abstract]
Outstanding debt	[1]	15,057			15,057							3,724
Value of Interest rate swap terminated | £										£ 1.0
Alliance Boots [Member]
Cash Flow Hedges [Abstract]
Outstanding debt		9,000			9,000
Notes Due 2024 [Member]
Cash Flow Hedges [Abstract]
Debt issuance	[1]	1,985			$ 1,985							0
Maturity year	[1]				2024
Notes Due 2044 [Member]
Cash Flow Hedges [Abstract]
Debt issuance	[1]	1,491			$ 1,491							0
Maturity year	[1]				2044
Three-month LIBOR [Member]
Derivatives, Fair Value [Line Items]
Derivatives assets, Notional Amount		1,500			$ 1,500
Cash Flow Hedges [Abstract]
Derivative notional principal amount		1,500			$ 1,500
Three-month LIBOR [Member] | Contract One [Member]
Cash Flow Hedges [Abstract]
Debt instrument, maturity period					10 years
Cash paid to settle swap					$ 45
Three-month LIBOR [Member] | Contract Two [Member]
Cash Flow Hedges [Abstract]
Debt instrument, maturity period					30 years
Cash paid to settle swap					$ 18
Interest Rate Swap [Member]
Cash Flow Hedges [Abstract]
Derivative maturity date					Jul. 31, 2015
Interest Rate Swap [Member] | One-month LIBOR [Member]
Derivatives, Fair Value [Line Items]
Derivatives assets, Fair Value		$ 250			$ 250
Fixed interest rate percentage (in hundredths)		5.25%			5.25%			5.25%	5.25%
Interest Rate Swap [Member] | Six-month LIBOR [Member]
Derivatives, Fair Value [Line Items]
Derivatives assets, Fair Value		$ 750			$ 750
Fixed interest rate percentage (in hundredths)		5.25%			5.25%			5.25%	5.25%
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] | Interest Expense [Member]
Effect of Fair Value Hedges on Results of Operations [Abstract]
Gains and losses due to changes in fair value of derivative instruments		$ 7		$ 7	$ 13		$ 26
Warrants [Abstract]
Gains and losses due to changes in fair value of derivative instruments		7		7	13		26
Interest Rate Swap [Member] | Not Designated as Hedging Instrument [Member] | Interest Expense [Member]
Effect of Fair Value Hedges on Results of Operations [Abstract]
Gains and losses due to changes in fair value of derivative instruments		0			1
Warrants [Abstract]
Gains and losses due to changes in fair value of derivative instruments		0			1
Notes [Member] | Designated as Hedging Instrument [Member] | Interest Expense [Member]
Effect of Fair Value Hedges on Results of Operations [Abstract]
Gains and losses due to changes in fair value of derivative instruments		(7)		(8)	(13)		(25)
Warrants [Abstract]
Gains and losses due to changes in fair value of derivative instruments		(7)		(8)	(13)		(25)
Interest Rate Cap [Member]
Derivatives, Fair Value [Line Items]
Derivatives assets, Notional Amount								£ 1.5	€ 2,000
Cash Flow Hedges [Abstract]
Derivative notional principal amount								£ 1.5	€ 2,000
Derivative notional amount terminated | €											€ 600
Warrants [Member] | Other Income [Member]
Effect of Fair Value Hedges on Results of Operations [Abstract]
Gains and losses due to changes in fair value of derivative instruments		449		119	1,298		275
Warrants [Abstract]
Gains and losses due to changes in fair value of derivative instruments		449		$ 119	1,298		$ 275
Foreign Currency Forwards [Member] | Not Designated as Hedging Instrument [Member] | Selling, General and Administrative Expenses [Member]
Effect of Fair Value Hedges on Results of Operations [Abstract]
Gains and losses due to changes in fair value of derivative instruments		49			38
Warrants [Abstract]
Gains and losses due to changes in fair value of derivative instruments		49			38
Foreign Currency Forwards [Member] | Not Designated as Hedging Instrument [Member] | Other Income [Member]
Effect of Fair Value Hedges on Results of Operations [Abstract]
Gains and losses due to changes in fair value of derivative instruments		7			17
Warrants [Abstract]
Gains and losses due to changes in fair value of derivative instruments		7			17
Second Step Transaction Foreign Currency Forwards [Member] | Not Designated as Hedging Instrument [Member] | Other Income [Member]
Effect of Fair Value Hedges on Results of Operations [Abstract]
Gains and losses due to changes in fair value of derivative instruments		0			(166)
Warrants [Abstract]
Gains and losses due to changes in fair value of derivative instruments		$ 0			$ (166)
Warrants Exercisable in March 2016 [Member]
Class of Warrant or Right [Line Items]
Warrant issued to purchase common stock (in share) | shares		22,696,912			22,696,912			22,696,912	22,696,912
Warrant exercise price (in dollars per share) | $ / shares		$ 51.50			$ 51.50
Warrants Exercisable in March 2017 [Member]
Class of Warrant or Right [Line Items]
Warrant issued to purchase common stock (in share) | shares		22,696,912			22,696,912			22,696,912	22,696,912
Warrant exercise price (in dollars per share) | $ / shares		$ 52.50			$ 52.50
Other Current Assets [Member] | Interest Rate Swap [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivatives assets, Notional Amount	[2]	$ 1,528			$ 1,528
Derivatives assets, Fair Value		0			0
Cash Flow Hedges [Abstract]
Derivative notional principal amount	[2]	1,528			1,528
Other Current Assets [Member] | Basis Swaps [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivatives assets, Notional Amount	[2]	2			2
Derivatives assets, Fair Value		0			0
Cash Flow Hedges [Abstract]
Derivative notional principal amount	[2]	2			2
Other Current Assets [Member] | Interest Rate Cap [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivatives assets, Notional Amount	[2]	3,830			3,830
Derivatives assets, Fair Value		0			0
Cash Flow Hedges [Abstract]
Derivative notional principal amount	[2]	3,830			3,830
Other Current Assets [Member] | Foreign Currency Forwards [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivatives assets, Notional Amount	[2]	1,768			1,768
Derivatives assets, Fair Value		11			11
Cash Flow Hedges [Abstract]
Derivative notional principal amount	[2]	1,768			1,768
Other Non-currents Assets [Member] | Interest Rate Swap [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivatives assets, Notional Amount		1,000	[2]		1,000	[2]						1,000
Derivatives assets, Fair Value		29			29							16
Cash Flow Hedges [Abstract]
Derivative notional principal amount		1,000	[2]		1,000	[2]						1,000
Other Non-currents Assets [Member] | Warrants [Member] | Not Designated as Hedging Instrument [Member]
Warrants [Abstract]
Derivative asset		2,679			2,679							553
Other Noncurrent Liabilities [Member] | Cash Flow Hedging [Member] | Forward Interest Rate Swaps [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative liability, Notional Amount												1,500
Derivative liability, Fair value												$ 44
Other Current Liabilities [Member] | Foreign Currency Forwards [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivatives assets, Notional Amount	[2]	364			364
Derivatives assets, Fair Value		13			13
Cash Flow Hedges [Abstract]
Derivative notional principal amount	[2]	$ 364			$ 364

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

[2] Amounts are presented in U.S. dollar equivalents.