Available-for-Sale Investments (Details) (AmerisourceBergen Common Stock [Member], USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
Nov. 30, 2014	Nov. 30, 2013	Aug. 31, 2014
AmerisourceBergen Common Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Percentage of rights to acquire common share (in hundredths)	7.00%
Purchase price of shares	$ 0	$ 290
Unrealized holding gains on Available-for-sale investment	327	85	170
Available-for-sale investments at fair value	$ 1,044	$ 599	$ 887

This item represents the cost of equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments for other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of equity securities categorized neither as held-to-maturity nor as trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=28360136&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 320

-Section 50

-Paragraph 2

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6957658&loc=d3e62557-112803

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- Definition

Amount of unrealized gain before deducting unrealized loss on investments in debt and equity securities classified as available-for-sale securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563

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- Definition

Refers to the company's right to acquire common shares of subsidiary through open market transactions during the period.

+ References

No definition available.

+ Details

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Namespace Prefix:	wag_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration