Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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- Definition

Gains (losses) reclassified from CTA to income for the Company's outstanding net investment hedges

+ References

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- Definition

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+ References

No definition available.

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- Definition

Amount before tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 45
-Paragraph 1
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=114867106&loc=SL7669646-108580

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Derivative Instruments and Hedging Activities - Additional Information (Detail) € in Millions, ¥ in Billions	3 Months Ended		6 Months Ended
	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)	Mar. 31, 2019 EUR (€)	Mar. 31, 2019 JPY (¥)	Sep. 30, 2018 EUR (€)	Sep. 30, 2018 JPY (¥)
Derivative [Line Items]
Gains (losses) reclassified from CTA to income for the Company's outstanding net investment hedges \| $	$ 0	$ 0	$ 0	$ 0
Foreign Currency Denominated Debt [Member]
Derivative [Line Items]
Notional amount \| ¥						¥ 35		¥ 35
58 million euro net investment hedge [Member] \| Foreign Currency Denominated Debt [Member]
Derivative [Line Items]
Notional amount					€ 58		€ 58
215 million EUR maturing in March 2020 [Member] \| Foreign Currency Denominated Debt [Member]
Derivative [Line Items]
Notional amount					215		215
One billion euro net investment hedge [Member] \| Foreign Currency Denominated Debt [Member]
Derivative [Line Items]
Notional amount					1,000,000,000,000		1,000,000,000,000
750 million euro net investment hedge [Member] \| Foreign Currency Denominated Debt [Member]
Derivative [Line Items]
Notional amount					750		750
423 million euro net investment hedge [Member] \| Foreign Currency Denominated Debt [Member]
Derivative [Line Items]
Notional amount					€ 423		€ 423
Net Investment Hedging [Member]
Derivative [Line Items]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax \| $	$ 50,000,000	$ (100,000,000)	$ 84,000,000	$ (136,000,000)