Fair Value Measurements - Summary of Activity Related to Equity Investments (Details) - USD ($) $ in Millions	12 Months Ended
Jan. 02, 2022	Jan. 03, 2021	Dec. 29, 2019
Equity Investment [Roll Forward]
Other assets, noncurrent	$ 10,216	$ 6,562
Equity securities \| Equity Investments with readily determinable value
Equity Investment [Roll Forward]
Marketable securities, noncurrent	1,884	1,481	$ 1,148
Equity, fair value adjustment	198	527
Equity investments, increase (decrease) from acquisition (sale) during period	205	(194)
Other assets, noncurrent	1,884	1,481
Equity securities \| Equity Investments without readily determinable value
Equity Investment [Roll Forward]
Equity, fair value adjustment	394	(55)
Equity investments, increase (decrease) from acquisition (sale) during period	(632)	81
Other assets, noncurrent	500	738
Equity securities without readily determinable fair value, amount	$ 500	$ 738	$ 712

Equity Investment [Roll Forward]

No definition available.

Name:	jnj_EquityInvestmentRollForward
Namespace Prefix:	jnj_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Equity Investments, Increase (Decrease) from Acquisition (Sale) During Period

+ References

No definition available.

+ Details

Name:	jnj_EquityInvestmentsIncreaseDecreasefromAcquisitionSaleDuringPeriod
Namespace Prefix:	jnj_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of addition (reduction) to the amount at which an instrument classified in shareholders' equity could be incurred (settled) in a current transaction between willing parties.

+ References

No definition available.

+ Details

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

- Definition

Amount of investment in equity security without readily determinable fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123583765&loc=SL75117539-209714

+ Details

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

- Definition

Amount of investment in marketable security, classified as noncurrent.

+ 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 210.5-02.12)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Definition

Amount of noncurrent assets classified as other.

+ 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 210.5-02.17)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Details

Name:	us-gaap_FairValueByAssetClassAxis=us-gaap_EquitySecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_OtherInvestmentNotReadilyMarketableAxis=jnj_EquityInvestmentswithReadilyDeterminableValueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_OtherInvestmentNotReadilyMarketableAxis=jnj_EquityInvestmentswithoutReadilyDeterminableValueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: