Financial Instruments (Details) (USD $) In Thousands, unless otherwise specified	Feb. 28, 2014	Aug. 31, 2013
Financial Instruments [Line Items]
Cash and cash equivalents	$ 929,869	$ 1,673,659
Current marketable securities	158,243	105,809
Noncurrent marketable securities	111,709	43,941
Total carrying value	1,199,821	1,823,409
Cash [Member]
Financial Instruments [Line Items]
Cash and cash equivalents	749,176	874,074
Current marketable securities	0	0
Noncurrent marketable securities	0	0
Total carrying value	749,176	874,074
Unrealized gains	0	0
Unrealized losses	0	0
Fair value	749,176	874,074
Money market funds [Member]
Financial Instruments [Line Items]
Cash and cash equivalents	152,684	732,530
Current marketable securities	0	0
Noncurrent marketable securities	0	0
Total carrying value	152,684	732,530
Unrealized gains	0	0
Unrealized losses	0	0
Tax-exempt municipal bonds [Member]
Financial Instruments [Line Items]
Cash and cash equivalents	602	2,055
Current marketable securities	61,224	69,621
Noncurrent marketable securities	48,190	24,070
Total carrying value	110,016	95,746
Unrealized gains	201	19
Unrealized losses	(6)	(54)
Commercial paper [Member]
Financial Instruments [Line Items]
Cash and cash equivalents	0	0
Current marketable securities	29,573	9,828
Noncurrent marketable securities	0	0
Total carrying value	29,573	9,828
Unrealized gains	3	0
Unrealized losses	0	0
Corporate bonds [Member]
Financial Instruments [Line Items]
Cash and cash equivalents	2,397	0
Current marketable securities	27,657	24,503
Noncurrent marketable securities	54,857	13,925
Total carrying value	84,911	38,428
Unrealized gains	143	6
Unrealized losses	(16)	(40)
Time deposits [Member]
Financial Instruments [Line Items]
Cash and cash equivalents	25,010
Current marketable securities	25,013
Noncurrent marketable securities	0
Total carrying value	50,023
Unrealized gains	0
Unrealized losses	0
Certificates of deposit [Member]
Financial Instruments [Line Items]
Cash and cash equivalents		65,000
Current marketable securities		1,200
Noncurrent marketable securities		0
Total carrying value		66,200
Unrealized gains		0
Unrealized losses		0
Other [Member]
Financial Instruments [Line Items]
Cash and cash equivalents	0	0
Current marketable securities	14,776	657
Noncurrent marketable securities	2,716	0
Total carrying value	17,492	657
Unrealized gains	4	0
Unrealized losses	0	0
Auction-rate securities [Member]
Financial Instruments [Line Items]
Cash and cash equivalents	0	0
Current marketable securities	0	0
Noncurrent marketable securities	5,946	5,946
Level 1 [Member] | Money market funds [Member]
Financial Instruments [Line Items]
Fair value	152,684	732,530
Level 2 [Member] | Tax-exempt municipal bonds [Member]
Financial Instruments [Line Items]
Fair value	110,211	95,711
Level 2 [Member] | Commercial paper [Member]
Financial Instruments [Line Items]
Fair value	29,576	9,828
Level 2 [Member] | Corporate bonds [Member]
Financial Instruments [Line Items]
Fair value	85,038	38,394
Level 2 [Member] | Time deposits [Member]
Financial Instruments [Line Items]
Fair value	50,023
Level 2 [Member] | Certificates of deposit [Member]
Financial Instruments [Line Items]
Fair value		66,200
Level 2 [Member] | Other [Member]
Financial Instruments [Line Items]
Fair value	17,496	657
Level 3 [Member] | Auction-rate securities [Member]
Financial Instruments [Line Items]
Total carrying value	$ 5,946	$ 5,946