Accumulated Other Comprehensive Loss (Summary of Changes in AOCI) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (8,800)	$ (9,892)	$ (8,800)	$ (9,892)	$ (11,788)	$ (10,149)	$ (9,519)	$ (9,333)
Other comprehensive (loss) income before reclassifications, net - Foreign Currency Translation	665	(435)	(780)	95
Amounts reclassified, pretax - Foreign Currency Translation	0	(1)	0	0
Tax benefit (expense) - Foreign Currency Translation	3	14	12	1
Other Comprehensive Income (Loss), Foreign Currency Transaction, Effect of Separation of Otis and Carrier	3,287		3,287
ASU 2018-02 adoption impact - Foreign Currency Translation				(8)
Other comprehensive (loss) income before reclassifications, net - Pension	(2,371)	(13)	(2,363)	(14)
Amounts reclassified, pretax - Pension	85	43	187	87
Tax benefit (expense) - Pension	568	(6)	537	(16)
Other Comprehensive Income (Loss), Defined Benefit Plan, Effect of Separation of Otis and Carrier	584		584
ASU 2018-02 adoption impact - Pension				(737)
Other comprehensive (loss) income before reclassifications, net - Unrealized Hedging (Losses) Gains	188	21	(215)	28
Amounts reclassified, pretax - Unrealized Hedging (Losses) Gains	27	16	56	20
Tax benefit (expense) - Unrealized Hedging (Losses) Gains	(52)	(12)	40	(15)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives, Effect of Separation of Otis and Carrier	4		4
ASU 2018-02 adoption impact - Unrealized Hedging (Losses) Gains				0
Other comprehensive (loss) income before reclassifications, net	(1,518)	(427)	(3,358)	109
Amounts reclassified, pre-tax	112	58	243	107
Tax benefit (expense)	519	(4)	589	(30)
Other Comprehensive Income (Loss), Effect of Separation of Otis and Carrier	3,875		3,875
ASU 2018-02 adoption impact				(745)
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(692)	(3,354)	(692)	(3,354)	(4,647)	(3,211)	(2,932)	(3,442)
Defined Benefit Pension and Post-retirement Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(7,827)	(6,398)	(7,827)	(6,398)	(6,693)	(6,772)	(6,422)	(5,718)
Unrealized hedging (losses) gains
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (281)	$ (140)	$ (281)	$ (140)	$ (448)	$ (166)	$ (165)	$ (173)