Available-for-Sale Investments (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended		9 Months Ended
	Mar. 18, 2016	May 31, 2016	May 31, 2015	May 31, 2016	May 31, 2015	Aug. 31, 2015
Summary of cost and fair value of available-for-sale securities [Abstract]
Amortized cost basis						$ 754
Gross unrealized gains						430
Gross unrealized losses						(1)
Fair value						1,183
Sale of acquired available-for-sale securities		$ 1	$ 0	$ 4	$ 0
AmerisourceBergen Common Stock [Member]
Summary of cost and fair value of available-for-sale securities [Abstract]
Amortized cost basis						717
Gross unrealized gains						430
Gross unrealized losses						0
Fair value						1,147
Warrant to purchase common stock (in shares)	22,696,912
Warrant exercise price (in dollars per share)	$ 51.50
Income from other comprehensive income to other income (expense)	$ 268
Other Investments [Member]
Summary of cost and fair value of available-for-sale securities [Abstract]
Amortized cost basis		37		37		37
Gross unrealized gains		0		0		0
Gross unrealized losses		(2)		(2)		(1)
Fair value		$ 35		$ 35		$ 36