Discontinued Operations and Disposal Groups (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Portfolio separation costs									$ 1,329
Income (loss) from discontinued operations attributable to common shareowners	$ (11)	$ 113	$ 9	$ (521)	$ 486	$ 190	$ 717	$ 634	(410)	$ 2,027	$ 4,053
Income (loss) from discontinued operations									(216)	4,091	5,776
Income tax expense from discontinued operations									151	1,874	1,528
Net income (loss) from discontinued operations									(367)	2,217	4,248
Less: Noncontrolling interest in subsidiaries’ earnings from discontinued operations									43	190	195
Net cash (used in) provided by operating activities									(728)	3,062	3,652
Net cash (used in) provided by investing activities									(241)	(416)	286
Net cash used in financing activities									(1,414)	(2,651)	(4,244)
Cash and cash equivalents					2,441					2,441
Accounts receivable, net					5,627					5,627
Contract assets, current					1,209					1,209
Inventories and contracts in progress, net					1,903					1,903
Other assets, current					434					434
Fixed assets, net					2,433					2,433
Operating lease right-of-use assets					1,347					1,347
Goodwill					11,454					11,454
Intangible assets, net					1,573					1,573
Other assets					3,402					3,402
Assets related to discontinued operations	64				31,823				64	31,823
Short-term borrowings					71					71
Accounts payable					3,003					3,003
Accrued employee compensation					1,022					1,022
Other accrued liabilities					3,518					3,518
Contract liabilities, current					2,899					2,899
Long-term debt, currently due					238					238
Long-term debt					87					87
Future pension and postretirement benefit obligations					1,015					1,015
Operating lease liabilities					1,051					1,051
Other long-term liabilities (1)					1,539					1,539
Liabilities related to discontinued operations	$ 116				14,443				116	14,443
Income from discontinued operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Portfolio separation costs									974
Income Tax Expense From Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Portfolio separation costs									(86)
Income From Continuing Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Portfolio separation costs									23
Income tax expense [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Portfolio separation costs									418
Otis [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (loss) from discontinued operations attributable to common shareowners									187	1,033	1,213
Research and development									38	163	185
Selling, general and administrative expense									450	1,906	1,636
Other income (expense), net									(65)	(40)	26
Non-operating (income) expense, net									3	4	(18)
Income (loss) from discontinued operations									340	1,709	1,935
Income tax expense from discontinued operations									116	525	561
Net income (loss) from discontinued operations									224	1,184	1,374
Less: Noncontrolling interest in subsidiaries’ earnings from discontinued operations									37	151	161
Cash and cash equivalents					1,446					1,446
Accounts receivable, net					2,899					2,899
Contract assets, current					530					530
Inventories and contracts in progress, net					571					571
Other assets, current					213					213
Fixed assets, net					747					747
Operating lease right-of-use assets					529					529
Goodwill					1,647					1,647
Intangible assets, net					490					490
Other assets					575					575
Assets related to discontinued operations					9,647					9,647
Short-term borrowings					33					33
Accounts payable					1,321					1,321
Accrued employee compensation					516					516
Other accrued liabilities					1,135					1,135
Contract liabilities, current					2,288					2,288
Long-term debt, currently due					1					1
Long-term debt					5					5
Future pension and postretirement benefit obligations					560					560
Operating lease liabilities					383					383
Other long-term liabilities (1)					514					514
Liabilities related to discontinued operations					6,756					6,756
Otis [Member] | Product [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales									1,123	5,669	5,636
Costs of Goods Sold									913	4,656	4,624
Otis [Member] | Service [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales									1,843	7,444	7,268
Costs of Goods Sold									1,157	4,635	4,568
Carrier [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (loss) from discontinued operations attributable to common shareowners									196	1,698	2,840
Research and development									98	400	399
Selling, general and administrative expense									669	2,888	2,566
Other income (expense), net									(30)	246	1,156
Non-operating (income) expense, net									17	(43)	(82)
Income (loss) from discontinued operations									304	2,409	3,841
Income tax expense from discontinued operations									102	672	967
Net income (loss) from discontinued operations									202	1,737	2,874
Less: Noncontrolling interest in subsidiaries’ earnings from discontinued operations									6	39	34
Cash and cash equivalents					995					995
Accounts receivable, net					2,728					2,728
Contract assets, current					679					679
Inventories and contracts in progress, net					1,332					1,332
Other assets, current					221					221
Fixed assets, net					1,686					1,686
Operating lease right-of-use assets					818					818
Goodwill					9,807					9,807
Intangible assets, net					1,083					1,083
Other assets					2,827					2,827
Assets related to discontinued operations					22,176					22,176
Short-term borrowings					38					38
Accounts payable					1,682					1,682
Accrued employee compensation					506					506
Other accrued liabilities					2,383					2,383
Contract liabilities, current					611					611
Long-term debt, currently due					237					237
Long-term debt					82					82
Future pension and postretirement benefit obligations					455					455
Operating lease liabilities					668					668
Other long-term liabilities (1)					1,025					1,025
Liabilities related to discontinued operations					$ 7,687					7,687
Carrier [Member] | Product [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales									3,143	15,337	15,657
Costs of Goods Sold									2,239	10,878	11,047
Carrier [Member] | Service [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales									741	3,247	3,239
Costs of Goods Sold									527	2,298	2,281
Separation Related Transactions [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (loss) from discontinued operations attributable to common shareowners									(793)	(704)	0
Selling, general and administrative expense									151	16	0
Other income (expense), net									(709)	(11)	0
Income (loss) from discontinued operations									(860)	(27)	0
Income tax expense from discontinued operations									$ (67)	$ 677	$ 0