Pension and Other Postretirement Benefits - Schedule of Obligations and Funded Status (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Settlements	$ (994)	$ (44)
Fair value of plan assets at beginning of year	5,348
Employer contributions	500
Fair value of plan assets at end of year	4,264	5,348
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at beginning of year	6,904
Service cost	22	54	$ 48
Interest cost	116	164	221
Settlements	968	51	73
Benefit obligation at end of year	4,594	6,904
Funded status	288	1,548
Less: Amounts attributed to joint venture partners	(25)	(45)
Net funded status	263	1,503
Noncurrent assets	164
Current liabilities	(10)	(11)
Noncurrent liabilities	(417)	(1,492)
Net amount recognized	(263)	(1,503)
Net actuarial loss	1,877	3,563
Prior service cost (benefit)	2	2
Total, before tax effect	1,879	3,565
Less: Amounts attributed to joint venture partners	38	57
Net amount recognized, before tax effect	1,841	3,508
Net actuarial loss (benefit)	(527)	462
Amortization of accumulated net actuarial (loss) benefit	(1,159)	(263)
Prior service cost (benefit)		1
Amortization of prior service (cost) benefit		(4)
Total, before tax effect	(1,686)	196
Less: Amounts attributed to joint venture partners	(19)	15
Net amount recognized, before tax effect	(1,667)	181
Pension Benefits [Member] | Change In Benefit Obligation [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at beginning of year	6,904	6,532
Service cost	22	56
Interest cost	120	168
Amendments		1
Actuarial losses (gains)	(305)	578
Settlements	(1,763)	(127)
Curtailments		6
Benefits paid	(362)	(381)
Divestitures		(2)
Foreign currency translation impact	(22)	73
Benefit obligation at end of year	4,594	6,904	6,532
Pension Benefits [Member] | Change In Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Settlements	(1,763)	(127)
Benefits paid	(356)	(379)
Foreign currency translation impact	(26)	61
Fair value of plan assets at beginning of year	5,356	5,015
Actual return on plan assets	513	455
Employer contributions	581	347
Participant contributions	5	10
Administrative expenses	(4)	(24)
Divestitures		(2)
Fair value of plan assets at end of year	4,306	5,356	5,015
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	4	5	4
Interest cost	15	19	36
Settlements	26		8
Funded status	710	892
Net funded status	710	892
Current liabilities	(60)	(65)
Noncurrent liabilities	(650)	(744)
Liabilities held for sale		(83)
Net amount recognized	(710)	(892)
Net actuarial loss	253	374
Prior service cost (benefit)	(125)	(156)
Total, before tax effect	128	218
Net amount recognized, before tax effect	128	218
Net actuarial loss (benefit)	(74)	133
Amortization of accumulated net actuarial (loss) benefit	(47)	(20)
Prior service cost (benefit)		(19)
Amortization of prior service (cost) benefit	31	17
Total, before tax effect	(90)	111
Net amount recognized, before tax effect	(90)	111
Other Postretirement Benefits [Member] | Change In Benefit Obligation [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at beginning of year	892	848
Service cost	4	5
Interest cost	15	19
Amendments		(19)
Actuarial losses (gains)	(78)	133
Curtailments		(1)
Benefits paid	(56)	(100)
Medicare Part D subsidy receipts	2	7
Divestitures	(69)
Benefit obligation at end of year	$ 710	$ 892	$ 848