Goodwill and Other Intangible Assets Carrying Amount of Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 30, 2017	Dec. 31, 2016
Goodwill [Roll Forward]
Goodwill	$ 5,166	$ 4,968
Goodwill Additions	375	245
Goodwill, purchase price allocation adjustment	(79)
Goodwill, Purchase Accounting Adjustments	(4)
Goodwill, Currency Translation Adjustments	46	(47)
Goodwill	5,504	5,166
U.S. Morning Foods
Goodwill [Roll Forward]
Goodwill	131	131
Goodwill Additions	0	0
Goodwill, purchase price allocation adjustment	0
Goodwill, Purchase Accounting Adjustments	0
Goodwill, Currency Translation Adjustments	0	0
Goodwill	131	131
U.S. Snacks
Goodwill [Roll Forward]
Goodwill	3,568	3,568
Goodwill Additions	0	0
Goodwill, purchase price allocation adjustment	0
Goodwill, Purchase Accounting Adjustments	0
Goodwill, Currency Translation Adjustments	0	0
Goodwill	3,568	3,568
U.S. Specialty
Goodwill [Roll Forward]
Goodwill	82	82
Goodwill Additions	0	0
Goodwill, purchase price allocation adjustment	0
Goodwill, Purchase Accounting Adjustments	0
Goodwill, Currency Translation Adjustments	0	0
Goodwill	82	82
North America Other
Goodwill [Roll Forward]
Goodwill	457	456
Goodwill Additions	375	0
Goodwill, purchase price allocation adjustment	0
Goodwill, Purchase Accounting Adjustments	0
Goodwill, Currency Translation Adjustments	4	1
Goodwill	836	457
Europe
Goodwill [Roll Forward]
Goodwill	376	431
Goodwill Additions	0	4
Goodwill, purchase price allocation adjustment	0
Goodwill, Purchase Accounting Adjustments	0
Goodwill, Currency Translation Adjustments	38	(59)
Goodwill	414	376
Latin America
Goodwill [Roll Forward]
Goodwill	328	76
Goodwill Additions	0	241
Goodwill, purchase price allocation adjustment	(79)
Goodwill, Purchase Accounting Adjustments	(4)
Goodwill, Currency Translation Adjustments	(1)	11
Goodwill	244	328
Asia Pacific
Goodwill [Roll Forward]
Goodwill	224	224
Goodwill Additions	0	0
Goodwill, purchase price allocation adjustment	0
Goodwill, Purchase Accounting Adjustments	0
Goodwill, Currency Translation Adjustments	5	0
Goodwill	$ 229	$ 224

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=64834752&loc=SL49117168-202975

+ Details

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

- Definition

Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

+ References

+ Details

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

- Definition

Amount of foreign currency translation gain (loss) which increases (decreases) an asset representing future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

+ Details

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

- Definition

Amount of increase (decrease) from adjustments after acquisition date under purchase accounting of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 16
-URI http://asc.fasb.org/extlink&oid=73531572&loc=d3e961-128460

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

+ Details

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

- Definition

Amount of transfers into (out of) an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

+ Details

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

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=k_UsMorningFoodsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=k_UsSnacksMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=k_UsSpecialtyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=k_NorthAmericaOtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=us-gaap_EuropeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=us-gaap_LatinAmericaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=us-gaap_AsiaPacificMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: