Redeemable Noncontrolling Interests - Summary of Redeemable Noncontrolling Interests (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Mar. 31, 2019	Dec. 29, 2018
Increase (Decrease) in Temporary Equity [Roll Forward]
Balance, beginning of period	$ 92	$ 367
Decrease in redeemable noncontrolling interests due to redemptions	(70)	(383)
Increase in redeemable noncontrolling interests due to business acquisitions	0	6
Net income attributable to redeemable noncontrolling interests	(1)	7
Dividends paid	0	(10)
Effect of foreign currency translation loss attributable to redeemable noncontrolling interests	0	(2)
Change in fair value of redeemable securities	(4)	107
Balance, end of period	$ 17	$ 92

Temporary Equity, Acquisitions During Period

No definition available.

Name:	cvet_TemporaryEquityAcquisitionsDuringPeriod
Namespace Prefix:	cvet_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Temporary Equity, Changes In Fair Value

+ References

No definition available.

+ Details

Name:	cvet_TemporaryEquityChangesInFairValue
Namespace Prefix:	cvet_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Temporary Equity, Redemptions During Period

+ References

No definition available.

+ Details

Name:	cvet_TemporaryEquityRedemptionsDuringPeriod
Namespace Prefix:	cvet_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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

- Definition

As of the reporting date, the aggregate carrying amount of all noncontrolling interests which are redeemable by the (parent) entity (1) at a fixed or determinable price on a fixed or determinable date, (2) at the option of the holder of the noncontrolling interest, or (3) upon occurrence of an event that is not solely within the control of the (parent) entity. This item includes noncontrolling interest holder's ownership (or holders' ownership) regardless of the type of equity interest (common, preferred, other) including all potential organizational (legal) forms of the investee entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 480
-SubTopic 10
-Section S99
-Paragraph 3A
-Subparagraph (16)(c)
-URI http://asc.fasb.org/extlink&oid=65877616&loc=SL6540498-122764

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 480
-SubTopic 10
-Section S99
-Paragraph 3A
-Subparagraph 15
-URI http://asc.fasb.org/extlink&oid=65877616&loc=SL6540498-122764

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 480
-SubTopic 10
-Section S99
-Paragraph 3A
-Subparagraph (12)(c)
-URI http://asc.fasb.org/extlink&oid=65877616&loc=SL6540498-122764

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 480
-SubTopic 10
-Section S99
-Paragraph 3A
-Subparagraph 14
-URI http://asc.fasb.org/extlink&oid=65877616&loc=SL6540498-122764

+ Details

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

- Definition

Accretion of temporary equity during the period due to cash, stock, and in-kind dividends. This item is an adjustment to net income necessary to derive net income apportioned to common stockholders and is to be distinguished from Temporary Equity, Accretion of Dividends (Temporary Equity, Accretion of Dividends).

+ References

No definition available.

+ Details

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

- Definition

Adjustments to temporary equity resulting from foreign currency translation adjustments.

+ References

No definition available.

+ Details

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

- Definition

The portion of net income or loss attributable to temporary equity interest.

+ References

No definition available.

+ Details

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