Fair Value Measurements (Fair Value Techniques) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Carrying Amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term receivables	$ 214	$ 655
Customer Financing Notes Receivable	262	394
Short-Term Borrowings	(126)	(388)
Long-term debt (excluding capitalized leases)	(19,634)	(19,807)
Long-term liabilities	(80)	(283)
Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term receivables	204	586
Customer Financing Notes Receivable	260	366
Short-Term Borrowings	(126)	(388)
Long-term debt (excluding capitalized leases)	(22,254)	(21,525)
Long-term liabilities	(74)	(253)
Level 1 \| Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term receivables	0
Customer Financing Notes Receivable	0
Short-Term Borrowings	0
Long-term debt (excluding capitalized leases)	0
Long-term liabilities	0
Level 2 \| Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term receivables	204
Customer Financing Notes Receivable	260
Short-Term Borrowings	0
Long-term debt (excluding capitalized leases)	(21,883)
Long-term liabilities	(74)
Level 3 \| Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term receivables	0
Customer Financing Notes Receivable	0
Short-Term Borrowings	(126)
Long-term debt (excluding capitalized leases)	(371)
Long-term liabilities	$ 0

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This element is used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. This element represents the fair value of customer financing notes receivable.

+ References

No definition available.

+ Details

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Namespace Prefix:	utx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This element is used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. This element represents the fair value of long-term borrowings (excluding capitalized leases).

+ References

No definition available.

+ Details

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Namespace Prefix:	utx_
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Balance Type:	credit
Period Type:	instant

- Definition

This element is used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. This element represents the fair value of long-term receivables.

+ References

No definition available.

+ Details

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Balance Type:	debit
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- Definition

This element is used in connection with the recurring fair value measurement disclosures required in the footnote disclosures to the financial statements. This element represents the fair value of lother long-term liabilities.

+ References

No definition available.

+ Details

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- Definition

+ References

No definition available.

+ Details

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