Accumulated Other Comprehensive Loss - Reclassifications (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ 1,158	$ 1,332	$ 1,522
Other (expense) income, net	113	(32)	70
Assets held for sale	104	1,889
Net loss (gain) on sale of businesses	121	(113)	0
Total before tax	10,237	991	(2,701)
Income tax expense	61	557	668
Net of tax	10,298	1,548	$ (2,033)
Decrease (Increase) in Net Income/Loss | Interest rate swap
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense		22
Income tax expense		(5)
Net of tax		17
Decrease (Increase) in Net Income/Loss | Defined benefit plans
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax	67	658
Income tax expense	(16)	(165)
Net of tax	51	493
Decrease (Increase) in Net Income/Loss | Net actuarial loss
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other (expense) income, net	82	121
Assets held for sale	(24)
Net loss (gain) on sale of businesses	(2)
Net loss (gain) on sale of businesses, including held for sale	(22)
Decrease (Increase) in Net Income/Loss | Settlement charge
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other (expense) income, net		(2)
Decrease (Increase) in Net Income/Loss | Prior service cost
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other (expense) income, net	(15)
Net loss (gain) on sale of businesses		539
Decrease (Increase) in Net Income/Loss | Foreign currency adjustment
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Assets held for sale	389
Net loss (gain) on sale of businesses	(7)	112
Net loss (gain) on sale of businesses, including held for sale	382
Income tax expense		0
Net of tax		$ 112
Decrease (Increase) in Net Income/Loss | Defined benefit plans and foreign currency adjustment
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense	0
Net of tax	$ 360