Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ 38,257	$ 25,404	$ 26,001
Other comprehensive income (loss) before reclassification adjustments, pretax	170	1,766	(949)
Tax	(150)	(526)	293
Other comprehensive income (loss) before reclassification adjustments, net of taxes	20	1,240	(656)
Reclassification adjustments, pretax	(446)	658	287
Tax	87	(142)	(72)
Reclassification adjustments, net of taxes	(359)	516	215
Other comprehensive income (loss), net of taxes	(339)	1,756	(441)
Spin-off of Organon & Co.		5,091
Ending balance	46,058	38,257	25,404
Derivatives
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	144	(266)	31
Other comprehensive income (loss) before reclassification adjustments, pretax	684	333	(383)
Tax	(143)	(75)	84
Other comprehensive income (loss) before reclassification adjustments, net of taxes	541	258	(299)
Reclassification adjustments, pretax	(775)	192	2
Tax	163	(40)	0
Reclassification adjustments, net of taxes	(612)	152	2
Other comprehensive income (loss), net of taxes	(71)	410	(297)
Spin-off of Organon & Co.	0
Ending balance	73	144	(266)
Investments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	0	0	18
Other comprehensive income (loss) before reclassification adjustments, pretax	0	0	3
Tax	0	0	0
Other comprehensive income (loss) before reclassification adjustments, net of taxes	0	0	3
Reclassification adjustments, pretax	0	0	(21)
Tax	0	0	0
Reclassification adjustments, net of taxes	0	0	(21)
Other comprehensive income (loss), net of taxes	0	0	(18)
Spin-off of Organon & Co.	0
Ending balance	0	0	0
Employee Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(2,743)	(4,540)	(4,261)
Other comprehensive income (loss) before reclassification adjustments, pretax	70	1,737	(633)
Tax	12	(332)	120
Other comprehensive income (loss) before reclassification adjustments, net of taxes	82	1,405	(513)
Reclassification adjustments, pretax	329	466	306
Tax	(76)	(102)	(72)
Reclassification adjustments, net of taxes	253	364	234
Other comprehensive income (loss), net of taxes	335	1,769	(279)
Spin-off of Organon & Co.	28
Ending balance	(2,408)	(2,743)	(4,540)
Pension Plan Net Loss
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Pension and other postretirement benefit plans, net loss and prior service (credit) included in AOCI	3,100	3,600
Other Postretirement Benefit Plan Net Gain
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Pension and other postretirement benefit plans, net loss and prior service (credit) included in AOCI	(446)	(473)
Pension Plan Prior Service Credit
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Pension and other postretirement benefit plans, net loss and prior service (credit) included in AOCI	(152)	(190)
Other Postretirement Benefit Plan Prior Service Credit
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Pension and other postretirement benefit plans, net loss and prior service (credit) included in AOCI	(135)	(181)
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(1,830)	(1,828)	(1,981)
Other comprehensive income (loss) before reclassification adjustments, pretax	(584)	(304)	64
Tax	(19)	(119)	89
Other comprehensive income (loss) before reclassification adjustments, net of taxes	(603)	(423)	153
Reclassification adjustments, pretax	0	0	0
Tax	0	0	0
Reclassification adjustments, net of taxes	0	0	0
Other comprehensive income (loss), net of taxes	(603)	(423)	153
Spin-off of Organon & Co.	421
Ending balance	(2,433)	(1,830)	(1,828)
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(4,429)	(6,634)	(6,193)
Spin-off of Organon & Co.	449	449
Ending balance	$ (4,768)	$ (4,429)	$ (6,634)