Represents the amount of loss from impairment of long term investment.

No definition available.

Name:	ctrp_LossFromImpairmentOfLongTermInvestment
Namespace Prefix:	ctrp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the total number seats of Board of directors

+ References

No definition available.

+ Details

Name:	ctrp_NumberOfBoardOfDirectorsSeats
Namespace Prefix:	ctrp_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the number of seats of board of directors allocated.

+ References

No definition available.

+ Details

Name:	ctrp_NumberOfSeatsAllocated
Namespace Prefix:	ctrp_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of investee's equity interest owned by the investor.

+ References

No definition available.

+ Details

Name:	ctrp_PurchaseOfSharesPercentageOfEquityInterestPurchasedAggregate
Namespace Prefix:	ctrp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of investee's voting power equity interest owned by the investor.

+ References

No definition available.

+ Details

Name:	ctrp_PurchaseOfSharesPercentageOfEquityInterestPurchasedAggregateVotingPower
Namespace Prefix:	ctrp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Purchase of Shares, Price per Share

+ References

No definition available.

+ Details

Name:	ctrp_PurchaseOfSharesPricePerShare
Namespace Prefix:	ctrp_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Purchase of Shares, Shares Purchased

+ References

No definition available.

+ Details

Name:	ctrp_PurchaseOfSharesSharesPurchased
Namespace Prefix:	ctrp_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor 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 50
-Paragraph 5
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563

Reference 3: 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

+ Details

Name:	us-gaap_AvailableForSaleSecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount before tax and reclassification adjustments of unrealized holding gain (loss) on available-for-sale securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=36458714&loc=SL7669646-108580

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=36458714&loc=d3e637-108580

+ Details

Name:	us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount after tax, before reclassification adjustments, of unrealized holding gain (loss) on available-for-sale securities.

+ References

+ Details

Name:	us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash outflow associated with the purchase of all investments (debt, security, other) during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Investing Activities
-URI http://asc.fasb.org/extlink&oid=6516133

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3213-108585

+ Details

Name:	us-gaap_PaymentsToAcquireInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_ScheduleOfInvestmentsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Price of a single share of a number of saleable stocks of a company.

+ References

No definition available.

+ Details

Name:	us-gaap_SharePrice
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	invest_InvestmentIssuerAxis=ctrp_EHiAutoServicesLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=ctrp_AdsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_CommonStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentIssuerAxis=ctrp_EasyGoIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_SeriesBPreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_SeriesCPreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentIssuerAxis=ctrp_TuniuCorporationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ctrp_PurchaseOfStockAxis=us-gaap_IPOMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentIssuerAxis=ctrp_DiningSecretaryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentIssuerAxis=ctrp_HappyCityHoldingsLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentIssuerAxis=ctrp_TravelAgencyFocusingOnTeenagerMarketMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentIssuerAxis=ctrp_BigDataAdvertisementCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

INVESTMENTS (Details 4) $ / shares in Units, ¥ in Thousands, $ in Millions	1 Months Ended								9 Months Ended		12 Months Ended
	Nov. 30, 2014 shares	Aug. 31, 2014 USD ($)	Aug. 31, 2014 CNY (¥)	May. 31, 2014 USD ($) $ / shares shares	May. 31, 2014 CNY (¥) shares	Dec. 31, 2013 USD ($)	Jun. 30, 2013 USD ($)	Nov. 30, 2010 USD ($)	Sep. 30, 2015 USD ($) item $ / shares	Sep. 30, 2015 CNY (¥)	Dec. 31, 2014 USD ($) item	Dec. 31, 2014 CNY (¥)	Sep. 30, 2015 CNY (¥) item
eHi
Investment
Total consideration of acquisition									$ 113.0	¥ 717,000
Voting power interest held (as a percent)									19.90%				19.90%
Purchase of Shares Percentage of Equity Interest Purchased Aggregate									14.00%				14.00%
Number Of Seats Allocated \| item									1				1
Number Of Board Of Directors Seats \| item									7				7
Increase/Decrease in fair value of the investment credited to other comprehensive income \| ¥										37,000
eHi \| ADS
Investment
Closing stock price (in dollars per share) \| $ / shares									$ 11.59
eHi \| Ordinary shares
Investment
Total consideration of acquisition \| $						$ 107.0
Purchase of Shares, Shares Purchased \| shares	10,000,000
Easy Go
Investment
Total consideration of acquisition									$ 101.0	643,000
Increase/Decrease in fair value of the investment credited to other comprehensive income \| ¥										298,000
Easy Go \| Series B Preferred Shares
Investment
Total consideration of acquisition \| $						$ 53.0
Easy Go \| Series C Preferred Stock
Investment
Total consideration of acquisition \| $		$ 53.0
Tuniu
Investment
Total consideration of acquisition				$ 15.0	¥ 93,000
Purchase of Shares Percentage of Equity Interest Purchased Aggregate											4.60%
Number Of Seats Allocated \| item											1
Number Of Board Of Directors Seats \| item											9
Fair value of available-for-sale investment									$ 49.0		$ 49.0		¥ 314,000
Increase/Decrease in fair value of the investment credited to other comprehensive income \| ¥										¥ 4,000
Tuniu \| IPO
Investment
Purchase of Shares, Shares Purchased \| shares				5,000,000	5,000,000
Tuniu \| ADS
Investment
Purchase of Shares, Shares Purchased \| shares				1,666,667	1,666,667
Closing stock price (in dollars per share) \| $ / shares									$ 11.87
Tuniu \| ADS \| IPO
Investment
Purchase of Shares Price Per Share \| $ / shares				$ 9
Tuniu \| Ordinary shares \| IPO
Investment
Purchase of Shares Price Per Share \| $ / shares				$ 3
Dining Secretary
Investment
Total consideration of acquisition \| $								$ 10.0
Loss from impairment of long-term investment (Note 9) \| ¥												¥ 33,000
Unrealized loss in other comprehensive income \| ¥												4,000
Happy City
Investment
Total consideration of acquisition \| $							$ 6.0
Increase/Decrease in fair value of the investment credited to other comprehensive income											$ 0.3	¥ 2,000
Travel agency focusing on teenager market \| Ordinary shares
Investment
Total consideration of acquisition \| ¥			¥ 81,000
Big-data service company
Investment
Total consideration of acquisition \| $		$ 10.0