Changes In Debt Obligations [Roll Forward]

No definition available.

Name:	ndaq_ChangesInDebtObligationsRollForward
Namespace Prefix:	ndaq_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Changes In Short-Term Debt Obligations [Roll Forward]

+ References

No definition available.

+ Details

Name:	ndaq_ChangesInShortTermDebtObligationsRollForward
Namespace Prefix:	ndaq_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Changes in Long-Term Debt Obligations [Roll Forward]

+ References

No definition available.

+ Details

Name:	ndaq_ChangesinLongTermDebtObligationsRollForward
Namespace Prefix:	ndaq_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Payments (Accretions) And Other Of Long-Term And Short-Term Debt

+ References

No definition available.

+ Details

Name:	ndaq_PaymentsAccretionsAndOtherOfLongTermAndShortTermDebt
Namespace Prefix:	ndaq_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Payments (Accretions) And Other of Long-term Debt

+ References

No definition available.

+ Details

Name:	ndaq_PaymentsAccretionsAndOtherofLongtermDebt
Namespace Prefix:	ndaq_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The average effective interest rate during the reporting period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateDuringPeriod
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the aggregate of total long-term debt, including current maturities and short-term debt.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtLongtermAndShorttermCombinedAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_LongTermDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3255-108585

+ Details

Name:	us-gaap_ProceedsFromIssuanceOfDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3255-108585

+ Details

Name:	us-gaap_ProceedsFromIssuanceOfLongTermDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The net cash inflow or outflow for borrowing having initial term of repayment within one year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04(a))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690

+ Details

Name:	us-gaap_ProceedsFromRepaymentsOfShortTermDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash inflow from a borrowing having initial term of repayment within one year or the normal operating cycle, if longer.

+ References

+ Details

Name:	us-gaap_ProceedsFromShortTermDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19)(a))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16)(a)(1))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(13))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

Name:	us-gaap_ShortTermBorrowings
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_DebtInstrumentAxis=ndaq_FourHundredMillionTermLoanFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ShortTermDebtTypeAxis=us-gaap_CommercialPaperMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ShortTermDebtTypeAxis=ndaq_SeniorUnsecuredFloatingRateNotesDueMarch2019Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=ndaq_FivePointFiveFivePercentSeniorUnsecuredNotesDueJanuaryFifteenTwoThousandTwentyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=ndaq_ThreePointEightSevenFivePercentSeniorUnsecuredNotesDueJune72021Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=ndaq_FourPointTwoFivePercentSeniorUnsecuredNotesDueJune12024Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=ndaq_OnePointSevenFiveSeniorUnsecuredNotesDueMay192023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=ndaq_ThreePointEightFiveSeniorSecuredNotesDueJune302026Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=ndaq_OneBillionFiveYearRevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Debt Obligations (Changes in Debt Obligations) (Details) - USD ($)	9 Months Ended
	Sep. 30, 2018	Apr. 30, 2017	Jun. 30, 2016	May 31, 2016	May 31, 2014	Jun. 30, 2013	Jan. 31, 2010
Changes In Short-Term Debt Obligations [Roll Forward]
Short-term debt - commercial paper beginning balance	$ 978,000,000
Additions	3,192,000,000
Payments, Accretion and Other	(3,362,000,000)
Short-term debt - commercial paper ending balance	808,000,000
Changes in Long-Term Debt Obligations [Roll Forward]
Long-term debt obligations at beginning of period	3,229,000,000
Additions	0
Payments, Accretion and Other	(157,000,000)
Long-term debt obligations at end of period	3,072,000,000
Changes In Debt Obligations [Roll Forward]
Total debt obligations at beginning of period	4,207,000,000
Additions	3,192,000,000
Payments, Accretion and Other	(3,519,000,000)
Total debt obligations at end of period	3,880,000,000
$400 million senior unsecured term loan facility due November 25, 2019 (average interest rate of 3.37% for the period January 1, 2018 through September 30, 2018)
Changes in Long-Term Debt Obligations [Roll Forward]
Long-term debt obligations at beginning of period	100,000,000
Additions	0
Payments, Accretion and Other	0
Long-term debt obligations at end of period	100,000,000
Credit facility, borrowing capacity	$ 400,000,000
Interest rate during period	3.37%
Commercial paper
Changes In Short-Term Debt Obligations [Roll Forward]
Short-term debt - commercial paper beginning balance	$ 480,000,000
Additions	3,192,000,000
Payments, Accretion and Other	(3,363,000,000)
Short-term debt - commercial paper ending balance	309,000,000
Senior unsecured floating rate notes due March 22, 2019
Changes In Short-Term Debt Obligations [Roll Forward]
Short-term debt - commercial paper beginning balance	498,000,000
Additions	0
Payments, Accretion and Other	1,000,000
Short-term debt - commercial paper ending balance	499,000,000
Senior Notes \| 5.55% senior unsecured notes due January 15, 2020
Changes in Long-Term Debt Obligations [Roll Forward]
Long-term debt obligations at beginning of period	599,000,000
Additions	0
Payments, Accretion and Other	0
Long-term debt obligations at end of period	$ 599,000,000
Stated rate	5.55%						5.55%
Senior Notes \| 3.875% senior unsecured notes due June 7, 2021
Changes in Long-Term Debt Obligations [Roll Forward]
Long-term debt obligations at beginning of period	$ 716,000,000
Additions	0
Payments, Accretion and Other	(22,000,000)
Long-term debt obligations at end of period	$ 694,000,000
Stated rate	3.875%					3.875%
Senior Notes \| 4.25% senior unsecured notes due June 1, 2024
Changes in Long-Term Debt Obligations [Roll Forward]
Long-term debt obligations at beginning of period	$ 496,000,000
Additions	0
Payments, Accretion and Other	1,000,000
Long-term debt obligations at end of period	$ 497,000,000
Stated rate	4.25%				4.25%
Senior Notes \| 1.75% senior unsecured notes due May 19, 2023
Changes in Long-Term Debt Obligations [Roll Forward]
Long-term debt obligations at beginning of period	$ 712,000,000
Additions	0
Payments, Accretion and Other	(22,000,000)
Long-term debt obligations at end of period	$ 690,000,000
Stated rate	1.75%			1.75%
Senior Notes \| 3.85% senior unsecured notes due June 30, 2026
Changes in Long-Term Debt Obligations [Roll Forward]
Long-term debt obligations at beginning of period	$ 496,000,000
Additions	0
Payments, Accretion and Other	0
Long-term debt obligations at end of period	$ 496,000,000
Stated rate	3.85%		3.85%
Revolving Credit Facility \| $1 billion revolving credit commitment due April 25, 2022 (average interest rate of 2.74% for the period January 1, 2018 through September 30, 2018)
Changes in Long-Term Debt Obligations [Roll Forward]
Long-term debt obligations at beginning of period	$ 110,000,000
Additions	0
Payments, Accretion and Other	(114,000,000)
Long-term debt obligations at end of period	(4,000,000)
Credit facility, borrowing capacity	$ 1,000,000,000	$ 1,000,000,000
Interest rate during period	2.74%