Borrowings and Lines of Credit (Long-Term Debt) (Details) € in Millions, $ in Millions	9 Months Ended
	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 EUR (€)	Dec. 31, 2020 USD ($)	Sep. 30, 2020 EUR (€)
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 30,973			$ 31,470
Extinguishment of Debt, Amount		$ 703
Other (including finance leases)	272			292
Other (fair market value adjustments, (discounts)/premiums, and debt issuance costs)	69			106
Total long-term debt	31,042			31,576
Less: current portion	274			550
Long-term debt, net of current portion	30,768			31,026
Otis 3-Year Term Loan due 2023
Debt Instrument [Line Items]
Proceeds from Issuance of Debt		$ 1,000
Debt Instrument, Maturity Date, Description		2023
Carrier 3-Year Term Loan due 2023
Debt Instrument [Line Items]
Proceeds from Issuance of Debt		$ 1,750
Debt Instrument, Maturity Date, Description		2023
Notes 1.923% Due 2023
Debt Instrument [Line Items]
Proceeds from Issuance of Debt		$ 500
Debt Instrument, Interest Rate, Stated Percentage					1.923%
Debt Instrument, Maturity Date, Description		2023
Libor plus 0.45% floating rates due 2023
Debt Instrument [Line Items]
Proceeds from Issuance of Debt		$ 500
Debt Instrument, Interest Rate, Stated Percentage					0.45%
Debt Instrument, Maturity Date, Description		2023
Notes 2.056% Due 2025
Debt Instrument [Line Items]
Proceeds from Issuance of Debt		$ 1,300
Debt Instrument, Interest Rate, Stated Percentage					2.056%
Debt Instrument, Maturity Date, Description		2025
Notes 2.242% Due 2025
Debt Instrument [Line Items]
Proceeds from Issuance of Debt		$ 2,000
Debt Instrument, Interest Rate, Stated Percentage					2.242%
Debt Instrument, Maturity Date, Description		2025
Notes 2.293% Due 2027
Debt Instrument [Line Items]
Proceeds from Issuance of Debt		$ 500
Debt Instrument, Interest Rate, Stated Percentage					2.293%
Debt Instrument, Maturity Date, Description		2027
Notes 2.493% Due 2027
Debt Instrument [Line Items]
Proceeds from Issuance of Debt		$ 1,250
Debt Instrument, Interest Rate, Stated Percentage					2.493%
Debt Instrument, Maturity Date, Description		2027
Notes 2.565% Due 2030
Debt Instrument [Line Items]
Proceeds from Issuance of Debt		$ 1,500
Debt Instrument, Interest Rate, Stated Percentage					2.565%
Debt Instrument, Maturity Date, Description		2030
Notes 2.722% Due 2030
Debt Instrument [Line Items]
Proceeds from Issuance of Debt		$ 2,000
Debt Instrument, Interest Rate, Stated Percentage					2.722%
Debt Instrument, Maturity Date, Description		2030
Notes 3.112% Due 2040
Debt Instrument [Line Items]
Proceeds from Issuance of Debt		$ 750
Debt Instrument, Interest Rate, Stated Percentage					3.112%
Debt Instrument, Maturity Date, Description		2040
Notes 3.377% Due 2040
Debt Instrument [Line Items]
Proceeds from Issuance of Debt		$ 1,500
Debt Instrument, Interest Rate, Stated Percentage					3.377%
Debt Instrument, Maturity Date, Description		2040
Notes 3.362% Due 2050
Debt Instrument [Line Items]
Proceeds from Issuance of Debt		$ 750
Debt Instrument, Interest Rate, Stated Percentage					3.362%
Debt Instrument, Maturity Date, Description		2050
Notes 3.577% Due 2050
Debt Instrument [Line Items]
Proceeds from Issuance of Debt		$ 2,000
Debt Instrument, Interest Rate, Stated Percentage					3.577%
Debt Instrument, Maturity Date, Description		2050
Notes 8.750% Due 2021 [Member]
Debt Instrument [Line Items]
Repayments of Debt	$ 250
Debt Instrument, Interest Rate, Stated Percentage	8.75%		8.75%
Debt Instrument, Maturity Date, Description	2021
Long-term Debt, Gross	$ 0			250
Notes 3.650% Due 2023 [Member]
Debt Instrument [Line Items]
Repayments of Debt		$ 410
Debt Instrument, Interest Rate, Stated Percentage	3.65%		3.65%		3.65%
Debt Instrument, Maturity Date, Description	2023	2023
Long-term Debt, Gross	$ 171			171
EURIBOR plus 0.20% floating rate notes due 2020 [Member]
Debt Instrument [Line Items]
Repayments of Debt		$ 817
Debt Instrument, Interest Rate, Stated Percentage					0.20%
Debt Instrument, Maturity Date, Description		2020
Debt Instrument, Face Amount | €					€ 750
Notes 4.500% Due 2020 [Member]
Debt Instrument [Line Items]
Repayments of Debt		$ 1,250
Debt Instrument, Interest Rate, Stated Percentage					4.50%
Debt Instrument, Maturity Date, Description		2020
Note 1.125% Due 2021 [Member]
Debt Instrument [Line Items]
Repayments of Debt		$ 1,082
Debt Instrument, Interest Rate, Stated Percentage					1.125%
Debt Instrument, Maturity Date, Description		2021
Long-term Debt, Gross | €					€ 950
Notes 1.250% due 2023 [Member]
Debt Instrument [Line Items]
Repayments of Debt		$ 836
Debt Instrument, Interest Rate, Stated Percentage					1.25%
Debt Instrument, Maturity Date, Description		2023
Long-term Debt, Gross | €					€ 750
Notes 1.150% Due 2024 [Member]
Debt Instrument [Line Items]
Repayments of Debt		$ 841
Debt Instrument, Interest Rate, Stated Percentage					1.15%
Debt Instrument, Maturity Date, Description		2024
Long-term Debt, Gross | €					€ 750
Notes 1.875% Due 2026 [Member]
Debt Instrument [Line Items]
Repayments of Debt		$ 567
Debt Instrument, Interest Rate, Stated Percentage					1.875%
Debt Instrument, Maturity Date, Description		2026
Long-term Debt, Gross | €					€ 500
Notes 1.900% Due 2020 [Member]
Debt Instrument [Line Items]
Repayments of Debt		$ 1,000
Debt Instrument, Interest Rate, Stated Percentage					1.90%
Debt Instrument, Maturity Date, Description		2020
Notes 3.350% Due 2021 [Member]
Debt Instrument [Line Items]
Repayments of Debt		$ 1,000
Debt Instrument, Interest Rate, Stated Percentage					3.35%
Debt Instrument, Maturity Date, Description		2021
LIBOR plus 0.650% floating rate notes due 2021 [Member]
Debt Instrument [Line Items]
Repayments of Debt		$ 750
Debt Instrument, Interest Rate, Stated Percentage					0.65%
Debt Instrument, Maturity Date, Description		2021
Notes 1.950% Due 2021 [Member]
Debt Instrument [Line Items]
Repayments of Debt		$ 750
Debt Instrument, Interest Rate, Stated Percentage					1.95%
Debt Instrument, Maturity Date, Description		2021
Notes 2.300% Due 2022 [Member]
Debt Instrument [Line Items]
Repayments of Debt		$ 500
Debt Instrument, Interest Rate, Stated Percentage					2.30%
Debt Instrument, Maturity Date, Description		2022
Notes 3.100% Due 2022 [Member]
Debt Instrument [Line Items]
Repayments of Debt		$ 2,300
Debt Instrument, Interest Rate, Stated Percentage					3.10%
Debt Instrument, Maturity Date, Description		2022
Notes 2.800% Due 2024 [Member]
Debt Instrument [Line Items]
Repayments of Debt		$ 800
Debt Instrument, Interest Rate, Stated Percentage					2.80%
Debt Instrument, Maturity Date, Description		2024
Notes 4.875% Due 2020 [Member]
Debt Instrument [Line Items]
Repayments of Debt		$ 171
Debt Instrument, Interest Rate, Stated Percentage					4.875%
Debt Instrument, Maturity Date, Description		2020
Notes 3.650% Due 2023 Feb2020
Debt Instrument [Line Items]
Repayments of Debt		$ 1,669
Debt Instrument, Interest Rate, Stated Percentage					3.65%
Debt Instrument, Maturity Date, Description		2023
Notes 2.650% Due 2026 [Member]
Debt Instrument [Line Items]
Repayments of Debt		$ 431
Debt Instrument, Interest Rate, Stated Percentage	2.65%		2.65%		2.65%
Debt Instrument, Maturity Date, Description	2026	2026
Long-term Debt, Gross	$ 719			719
Notes 3.100% Due 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.10%		3.10%
Debt Instrument, Maturity Date, Description	2021
Long-term Debt, Gross	$ 250			250
Notes 2.800% Due 2022 [Member]
Debt Instrument [Line Items]
Repayments of Debt	$ 1,100
Debt Instrument, Interest Rate, Stated Percentage	2.80%		2.80%
Debt Instrument, Maturity Date, Description	2022
Long-term Debt, Gross	$ 0			1,100
Notes 2.500% Due 2022
Debt Instrument [Line Items]
Repayments of Debt	$ 1,100
Debt Instrument, Interest Rate, Stated Percentage	2.50%		2.50%
Debt Instrument, Maturity Date, Description	2022
Long-term Debt, Gross	$ 0			1,100
Notes 3.700% Due 2023 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.70%		3.70%
Debt Instrument, Maturity Date, Description	2023
Long-term Debt, Gross	$ 400			400
Notes 3.200% Due 2024 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.20%		3.20%
Debt Instrument, Maturity Date, Description	2024
Long-term Debt, Gross	$ 950			950
Notes 3.150% Due 2024
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.15%		3.15%
Debt Instrument, Maturity Date, Description	2024
Long-term Debt, Gross	$ 300			300
Notes 3.950% Due 2025 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.95%		3.95%
Debt Instrument, Maturity Date, Description	2025
Long-term Debt, Gross	$ 1,500			1,500
Notes 3.125% Due 2027 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.125%		3.125%
Debt Instrument, Maturity Date, Description	2027
Long-term Debt, Gross	$ 1,100			1,100
Notes 3.500% Due 2027 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.50%		3.50%
Debt Instrument, Maturity Date, Description	2027
Long-term Debt, Gross	$ 1,300			1,300
Notes 7.200% Due 2027
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	7.20%		7.20%
Debt Instrument, Maturity Date, Description	2027
Long-term Debt, Gross	$ 382			382
Notes 7.100% Due 2027 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	7.10%		7.10%
Debt Instrument, Maturity Date, Description	2027
Long-term Debt, Gross	$ 141			141
Notes 6.700% Due 2028 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.70%		6.70%
Debt Instrument, Maturity Date, Description	2028
Long-term Debt, Gross	$ 400			400
Notes 7.000% Due 2028
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	7.00%		7.00%
Debt Instrument, Maturity Date, Description	2028
Long-term Debt, Gross	$ 185			185
Notes 4.125% Due 2028 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.125%		4.125%
Debt Instrument, Maturity Date, Description	2028
Long-term Debt, Gross	$ 3,000			3,000
Notes 7.500% Due 2029 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	7.50%		7.50%
Debt Instrument, Maturity Date, Description	2029
Long-term Debt, Gross	$ 550			550
Notes 2.150% Due 2030 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.15%		2.15%
Debt Instrument, Maturity Date, Description	2030
Long-term Debt, Gross	$ 585			612
Debt Instrument, Face Amount | €			€ 500
Notes 2.250% Due 2030
Debt Instrument [Line Items]
Proceeds from Issuance of Debt		$ 1,000
Debt Instrument, Interest Rate, Stated Percentage	2.25%		2.25%		2.25%
Debt Instrument, Maturity Date, Description	2030	2030
Long-term Debt, Gross	$ 1,000			1,000
Notes 5.400% Due 2035 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.40%		5.40%
Debt Instrument, Maturity Date, Description	2035
Long-term Debt, Gross	$ 600			600
Notes 6.050% Due 2036 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.05%		6.05%
Debt Instrument, Maturity Date, Description	2036
Long-term Debt, Gross	$ 600			600
Notes 6.800% Due 2036 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.80%		6.80%
Debt Instrument, Maturity Date, Description	2036
Long-term Debt, Gross	$ 134			134
Notes 7.000% Due 2038 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	7.00%		7.00%
Debt Instrument, Maturity Date, Description	2038
Long-term Debt, Gross	$ 159			159
Notes 6.125% Due 2038 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.125%		6.125%
Debt Instrument, Maturity Date, Description	2038
Long-term Debt, Gross	$ 1,000			1,000
Notes 4.450% Due 2038 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.45%		4.45%
Debt Instrument, Maturity Date, Description	2038
Long-term Debt, Gross	$ 750			750
Notes 5.700% Due 2040 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.70%		5.70%
Debt Instrument, Maturity Date, Description	2040
Long-term Debt, Gross	$ 1,000			1,000
Notes 4.875% Due 2040
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.875%		4.875%
Debt Instrument, Maturity Date, Description	2040
Long-term Debt, Gross	$ 600			600
Notes 4.700% Due 2041
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.70%		4.70%
Debt Instrument, Maturity Date, Description	2041
Long-term Debt, Gross	$ 425			425
Notes 4.500% Due 2042 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.50%		4.50%
Debt Instrument, Maturity Date, Description	2042
Long-term Debt, Gross	$ 3,500			3,500
Notes 4.800% Due 2043 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.80%		4.80%
Debt Instrument, Maturity Date, Description	2043
Long-term Debt, Gross	$ 400			400
Notes 4.200% Due 2044
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.20%		4.20%
Debt Instrument, Maturity Date, Description	2044
Long-term Debt, Gross	$ 300			300
Notes 4.150% Due 2045 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.15%		4.15%
Debt Instrument, Maturity Date, Description	2045
Long-term Debt, Gross	$ 850			850
Notes 3.750% Due 2046 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.75%		3.75%
Debt Instrument, Maturity Date, Description	2046
Long-term Debt, Gross	$ 1,100			1,100
Notes 4.050% Due 2047 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.05%		4.05%
Debt Instrument, Maturity Date, Description	2047
Long-term Debt, Gross	$ 600			600
Notes 4.350% Due 2047 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.35%		4.35%
Debt Instrument, Maturity Date, Description	2047
Long-term Debt, Gross	$ 1,000			1,000
Notes 4.625% Due 2048 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.625%		4.625%
Debt Instrument, Maturity Date, Description	2048
Long-term Debt, Gross	$ 1,750			1,750
Notes 3.125% Due 2050
Debt Instrument [Line Items]
Proceeds from Issuance of Debt		$ 1,000
Debt Instrument, Interest Rate, Stated Percentage	3.125%		3.125%		3.125%
Debt Instrument, Maturity Date, Description	2050	2050
Long-term Debt, Gross	$ 1,000			1,000
Notes 1.900% due 2031
Debt Instrument [Line Items]
Proceeds from Issuance of Debt	$ 1,000
Debt Instrument, Interest Rate, Stated Percentage	1.90%		1.90%
Debt Instrument, Maturity Date, Description	2031
Long-term Debt, Gross	$ 1,000			0
Notes 2.820% due 2051
Debt Instrument [Line Items]
Proceeds from Issuance of Debt	$ 1,000
Debt Instrument, Interest Rate, Stated Percentage	2.82%		2.82%
Debt Instrument, Maturity Date, Description	2051
Long-term Debt, Gross	$ 1,000			$ 0