Pension and Postretirement Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2021

Retirement Benefits [Abstract]

Reconciliation of the beginning and ending balances of the benefit obligation and the fair value of plan assets

The following tables include a reconciliation of the beginning and ending balances of the benefit obligation and the fair value of plan assets as well as a summary of the related amounts recognized in the Company’s consolidated balance sheet as of December 31 of the respective years. 3M also has certain non-qualified unfunded pension and postretirement benefit plans, inclusive of plans related to supplement/excess benefits for employees impacted by particular relocations and other matters, that individually and in the aggregate are not significant and which are not included in the tables that follow. The obligations for these plans are included within other liabilities in the Company’s consolidated balance sheet and aggregated to less than $40 million as of December 31, 2021 and 2020.

	Qualified and Non-Pension Benefits								Postretirement Benefits
	United States				International
(Millions)	2021		2020		2021		2020		2021		2020
Change in benefit obligation
Benefit obligation at beginning of year	$	19,376	$	17,935	$	8,770	$	7,931	$	2,397	$	2,242
Acquisitions/Transfers	—		—		—		1		—		—
Service cost	286		261		164		152		53		43
Interest cost	360		499		98		117		43		62
Participant contributions	—		—		10		9		—		—
Foreign exchange rate changes	—		—		(325)		427		(4)		(14)
Plan amendments	—		—		1		—		—		—
Actuarial (gain) loss	(588)		1,785		(433)		464		(89)		176
Benefit payments	(1,330)		(1,104)		(298)		(274)		(113)		(107)
Settlements, curtailments, special termination benefits and other	—		—		(45)		(57)		(6)		(5)
Benefit obligation at end of year	$	18,104	$	19,376	$	7,942	$	8,770	$	2,281	$	2,397
Change in plan assets
Fair value of plan assets at beginning of year	17,127		16,099		8,194		6,923		1,376		1,338
Acquisitions/Transfers	—		—		—		—		—		—
Actual return on plan assets	1,079		2,071		321		1,102		93		147
Company contributions	77		61		100		92		3		3
Participant contributions	—		—		10		9		—		—
Foreign exchange rate changes	—		—		(265)		376		—		—
Benefit payments	(1,330)		(1,104)		(298)		(274)		(113)		(107)
Settlements, curtailments, special termination benefits and other	—		—		(46)		(34)		(6)		(5)
Fair value of plan assets at end of year	$	16,953	$	17,127	$	8,016	$	8,194	$	1,353	$	1,376
Funded status at end of year	$	(1,151)	$	(2,249)	$	74	$	(576)	$	(928)	$	(1,021)

Amounts recognized in the Consolidated Balance Sheet

Amounts recognized in the Consolidated Balance Sheet as of December 31, (Millions)	Qualified and Non-qualified Pension Benefits								Postretirement Benefits
	United States				International
	2021		2020		2021		2020		2021		2020
Non-current assets	$	—	$	—	$	943	$	630	$	—	$	—
Accrued benefit cost
Current liabilities	(59)		(52)		(14)		(15)		(5)		(4)
Non-current liabilities	(1,092)		(2,197)		(855)		(1,191)		(923)		(1,017)
Ending balance	$	(1,151)	$	(2,249)	$	74	$	(576)	$	(928)	$	(1,021)

Amounts recognized in accumulated other comprehensive income

Amounts recognized in accumulated other comprehensive income as of December 31, (Millions)	Qualified and Non-qualified Pension Benefits								Postretirement Benefits
	United States				International
	2021		2020		2021		2020		2021		2020
Net transition obligation (asset)	$	—	$	—	$	6	$	9	$	—	$	—
Net actuarial loss (gain)	4,991		6,157		960		1,570		538		702
Prior service cost (credit)	(80)		(104)		3		(2)		(197)		(230)
Ending balance	$	4,911	$	6,053	$	969	$	1,577	$	341	$	472

Amounts relating to pension plans with accumulated benefit obligations in excess of plan assets

The following table summarizes the total accumulated benefit obligations, the accumulated benefit obligations and fair value of plan assets for defined benefit pension plans with accumulated benefit obligations in excess of plan assets, and the projected benefit obligation and fair value of plan assets for defined benefit pension plans with projected benefit obligation in excess of plan assets as of December 31:

	Qualified and Non-qualified Pension Plans
	United States				International
(Millions)	2021		2020		2021		2020
Accumulated benefit obligation	$	17,305	$	18,441	$	7,484	$	8,181
Plans with accumulated benefit obligation in excess of plan assets
Accumulated benefit obligation	$	514	$	18,441	$	2,843	$	3,119
Fair value of plan assets	—		17,127		2,194		2,199
Plans with projected benefit obligation in excess of plan assets
Projected benefit obligation	$	18,104	$	19,376	$	3,204	$	3,528
Fair value of plan assets	16,953		17,127		2,335		2,322

Components of net periodic benefit cost (benefit)

Components of net periodic benefit cost and other supplemental information for the years ended December 31 follow:

	Qualified and Non-qualified Pension Benefits												Postretirement Benefits
	United States						International
(Millions)	2021		2020		2019		2021		2020		2019		2021		2020		2019
Net periodic benefit cost (benefit)
Operating expense
Service cost	$	286	$	261	$	251	$	164	$	152	$	131	$	53	$	43	$	43
Non-operating expense
Interest cost	360		499		620		98		117		156		43		62		82
Expected return on plan assets	(1,055)		(1,046)		(1,024)		(326)		(306)		(295)		(78)		(80)		(78)
Amortization of transition asset	—		—		—		2		2		—		—		—		—
Amortization of prior service benefit	(24)		(24)		(24)		(3)		(5)		(12)		(33)		(33)		(33)
Amortization of net actuarial loss	529		491		398		104		121		89		56		47		37
Settlements, curtailments, special termination benefits and other	24		16		70		3		1		10		3		3		5
Total non-operating expense (benefit)	(166)		(64)		40		(122)		(70)		(52)		(9)		(1)		13
Total net periodic benefit cost (benefit)	$	120	$	197	$	291	$	42	$	82	$	79	$	44	$	42	$	56
Other changes in plan assets and benefit obligations recognized in other comprehensive (income) loss
Amortization of transition asset	$	—	$	—	$	—	$	(2)	$	(2)	$	—	$	—	$	—	$	—
Prior service cost (benefit)	—		—		—		1		—		3		—		—		(171)
Amortization of prior service benefit	24		24		24		3		5		12		33		33		33
Net actuarial (gain) loss	(614)		760		910		(434)		(358)		340		(104)		108		117
Amortization of net actuarial loss	(529)		(491)		(398)		(104)		(121)		(89)		(56)		(47)		(37)
Foreign currency	—		—		—		(71)		79		7		(1)		(7)		(1)
Settlements, curtailments, special termination benefits and other	(23)		(16)		(35)		(1)		(1)		(8)		(3)		(3)		(5)
Total recognized in other comprehensive (income) loss	$	(1,142)	$	277	$	501	$	(608)	$	(398)	$	265	$	(131)	$	84	$	(64)
Total recognized in net periodic benefit cost (benefit) and other comprehensive (income) loss	$	(1,022)	$	474	$	792	$	(566)	$	(316)	$	344	$	(87)	$	126	$	(8)

Weighted-average assumptions used to determine benefit obligations and net cost

Weighted-average assumptions used to determine benefit obligations as of December 31

	Qualified and Non-qualified Pension Benefits												Postretirement Benefits
	United States						International
	2021		2020		2019		2021		2020		2019		2021		2020		2019
Discount rate	2.89	%	2.55	%	3.25	%	1.80	%	1.38	%	1.81	%	2.88	%	2.50	%	3.27	%
Compensation rate increase	3.21	%	3.21	%	3.21	%	2.86	%	2.88	%	2.88	%	N/A		N/A		N/A

Weighted-average assumptions used to determine net cost for years ended December 31

	Qualified and Non-qualified Pension Benefits												Postretirement Benefits
	United States						International
	2021		2020		2019		2021		2020		2019		2021		2020		2019
Discount rate - service cost	2.81	%	3.41	%	4.44	%	1.23	%	1.61	%	2.39	%	3.21	%	3.45	%	4.53	%
Discount rate - interest cost	1.92	%	2.87	%	4.02	%	1.13	%	1.61	%	2.26	%	2.20	%	3.00	%	4.15	%
Expected return on assets	6.50	%	6.75	%	7.00	%	4.36	%	4.70	%	4.90	%	6.15	%	6.32	%	6.43	%
Compensation rate increase	3.21	%	3.21	%	4.10	%	2.88	%	2.88	%	2.89	%	N/A		N/A		N/A

Estimated future pension and postretirement benefit payments

The following table provides the estimated pension and postretirement benefit payments that are payable from the plans to participants.

	Qualified and Non-qualified Pension Benefits				Postretirement Benefits
(Millions)	United States		International
2022 Benefit Payments	$	1,120	$	271	$	131
2023 Benefit Payments	1,123		277		137
2024 Benefit Payments	1,122		290		144
2025 Benefit Payments	1,119		305		149
2026 Benefit Payments	1,118		320		155
Next five years	5,461		1,724		796

Fair values of the assets held by the plans by asset category

The fair values of the assets held by the U.S. pension plans by asset class are as follows:

	Fair Value Measurements Using Inputs Considered as												Fair Value at December 31,
	Level 1				Level 2				Level 3
Asset Class (Millions)	2021		2020		2021		2020		2021		2020		2021		2020
Equities
U.S. equities	$	1,875	$	2,082	$	—	$	—	$	—	$	—	$	1,875	$	2,082
Non-U.S. equities	1,465		2,041		—		—		—		—		1,465		2,041
Index and long/short equity funds*													404		433
Total Equities	3,340		4,123		—		—		—		—		3,744		4,556
Fixed Income
U.S. government securities	1,417		1,301		716		978		—		—		2,133		2,279
Non-U.S. government securities	—		—		89		71		—		—		89		71
Preferred and convertible securities	—		—		54		55		—		—		54		55
U.S. corporate bonds	11		10		4,620		4,501		—		—		4,631		4,511
Non-U.S. corporate bonds	—		—		883		820		—		—		883		820
Derivative instruments	11		(4)		6		7		—		—		17		3
Other*													132		71
Total Fixed Income	1,439		1,307		6,368		6,432		—		—		7,939		7,810
Private Equity
Growth equity	58		70		—		—		—		—		58		70
Partnership investments*													2,003		1,801
Total Private Equity	58		70		—		—		—		—		2,061		1,871
Absolute Return
Fixed income and other	1		—		166		134		—		—		167		134
Hedge fund/fund of funds*													1,943		2,046
Partnership investments*													617		567
Total Absolute Return	1		—		166		134		—		—		2,727		2,747
Cash and Cash Equivalents
Cash and cash equivalents	11		25		9		12		—		—		20		37
Repurchase agreements and derivative margin activity	—		—		—		(6)		—		—		—		(6)
Cash and cash equivalents, valued at net asset value*													678		475
Total Cash and Cash Equivalents	11		25		9		6		—		—		698		506
Total	$	4,849	$	5,525	$	6,543	$	6,572	$	—	$	—	$	17,169	$	17,490
Other items to reconcile to fair value of plan assets													(216)		(363)
Fair value of plan assets													$	16,953	$	17,127

* In accordance with ASC 820-10, certain investments that are measured at fair value using the net asset value (NAV) per share (or its equivalent) as a practical expedient have not been classified in the fair value hierarchy. The NAV is based on the fair value of the underlying assets owned by the fund, minus its liabilities then divided by the number of units outstanding and is determined by the investment manager or custodian of the fund. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the fair value of plan assets.

The fair values of the assets held by the postretirement benefit plans by asset class are as follows:

	Fair Value Measurements Using Inputs Considered as												Fair Value at December 31,
	Level 1				Level 2				Level 3
Asset Class (Millions)	2021		2020		2021		2020		2021		2020		2021		2020
Equities
U.S. equities	$	292	$	347	$	—	$	—	$	—	$	—	$	292	$	347
Non-U.S. equities	80		103		—		—		—		—		80		103
Index and long/short equity funds*													28		31
Total Equities	372		450		—		—		—		—		400		481
Fixed Income
U.S. government securities	109		95		180		214		—		—		289		309
Non-U.S. government securities	—		—		7		6		—		—		7		6
U.S. corporate bonds	1		1		291		267		—		—		292		268
Non-U.S. corporate bonds	—		—		59		52		—		—		59		52
Derivative instruments	—		—		—		—		—		—		—		—
Other*													7		3
Total Fixed Income	110		96		537		539		—		—		654		638
Private Equity
Growth equity	3		3		—		—		—		—		3		3
Partnership investments*													107		95
Total Private Equity	3		3		—		—		—		—		110		98
Absolute Return
Fixed income and other	—		—		9		7		—		—		9		7
Hedge fund/fund of funds*													102		100
Partnership investments*													32		28
Total Absolute Return	—		—		9		7		—		—		143		135
Cash and Cash Equivalents
Cash and cash equivalents	20		25		—		1		—		—		20		26
Cash and cash equivalents, valued at net asset value*													36		23
Total Cash and Cash Equivalents	20		25		—		1		—		—		56		49
Total	$	505	$	574	$	546	$	547	$	—	$	—	$	1,363	$	1,401
Other items to reconcile to fair value of plan assets													(10)		(25)
Fair value of plan assets													$	1,353	$	1,376

*In accordance with ASC 820-10, certain investments that are measured at fair value using the NAV per share (or its equivalent) as a practical expedient have not been classified in the fair value hierarchy. The NAV is based on the fair value of the underlying assets owned by the fund, minus its liabilities then divided by the number of units outstanding and is determined by the investment manager or custodian of the fund. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the fair value of plan assets.

The fair values of the assets held by the international pension plans by asset class are as follows:

	Fair Value Measurements Using Inputs Considered as												Fair Value at December 31,
	Level 1				Level 2				Level 3
Asset Class (Millions)	2021		2020		2021		2020		2021		2020		2021		2020
Equities
Growth equities	$	315	$	547	$	181	$	209	$	—	$	—	$	496	$	756
Value equities	328		659		15		396		—		—		343		1,055
Core equities	107		46		547		99		5		4		659		149
Equities, valued at net asset value*													2		74
Total Equities	750		1,252		743		704		5		4		1,500		2,034
Fixed Income
Domestic government	73		71		1,039		1,045		4		5		1,116		1,121
Foreign government	22		33		458		476		—		—		480		509
Corporate debt securities	32		34		2,389		2,470		10		11		2,431		2,515
Fixed income securities, valued at net asset value*													893		563
Total Fixed Income	127		138		3,886		3,991		14		16		4,920		4,708
Private Equity
Real estate	2		128		58		86		5		5		65		219
Real estate, valued at net asset value*													163		92
Partnership investments*													226		116
Total Private Equity	2		128		58		86		5		5		454		427
Absolute Return
Derivatives	—		—		20		1		—		—		20		1
Insurance	—		—		—		—		504		555		504		555
Other	7		8		—		—		6		6		13		14
Other, valued at net asset value*													—		1
Hedge funds*													535		410
Total Absolute Return	7		8		20		1		510		561		1,072		981
Cash and Cash Equivalents
Cash and cash equivalents	145		149		46		51		—		—		191		200
Cash and cash equivalents, valued at net asset value*													1		1
Total Cash and Cash Equivalents	145		149		46		51		—		—		192		201
Total	$	1,031	$	1,675	$	4,753	$	4,833	$	534	$	586	$	8,138	$	8,351
Other items to reconcile to fair value of plan assets													(122)		(157)
Fair value of plan assets													$	8,016	$	8,194

*In accordance with ASC 820-10, certain investments that are measured at fair value using the NAV per share (or its equivalent) as a practical expedient have not been classified in the fair value hierarchy. The NAV is based on the fair value of the underlying assets owned by the fund, minus its liabilities then divided by the number of units outstanding and is determined by the investment manager or custodian of the fund. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the fair value of plan assets.