Borrowings: (Pre-Swap Borrowing) (Details 2) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014		Dec. 31, 2013
Debt Disclosure
Aggregate carrying amount of long-term borrowings before adjusting for unamortized discount and fair value adjustment	$ 39,684		$ 37,036
Less: net unamortized discount	866		872
Add: fair value adjustment	667	[1]	546	[1]
Long-Term Debt, including current portion	39,485		36,710
Less: current maturities	5,477		3,854
Total long-term debt (excluding current portion)	34,008		32,856
U.S. dollar notes and debentures
Debt Disclosure
Aggregate carrying amount of long-term borrowings before adjusting for unamortized discount and fair value adjustment	31,709		27,887
0.62% Notes and Debentures, maturing in 2014-2015
Debt Disclosure
Aggregate carrying amount of long-term borrowings before adjusting for unamortized discount and fair value adjustment	4,775		6,456
Debt instrument, stated interest rate percentage (as a percent)	0.62%
0.62% Notes and Debentures, maturing in 2014-2015 | IBM International Group Capital LLC
Debt Disclosure
Aggregate carrying amount of long-term borrowings before adjusting for unamortized discount and fair value adjustment			17
Percentage of ownership in indirect subsidiary (percent, expressed as a decimal)			100.00%
2.59% Notes and Debentures, maturing in 2016-2017
Debt Disclosure
Aggregate carrying amount of long-term borrowings before adjusting for unamortized discount and fair value adjustment	10,118		8,465
Debt instrument, stated interest rate percentage (as a percent)	2.59%
3.34% Notes and Debentures, maturing in 2018-2021
Debt Disclosure
Aggregate carrying amount of long-term borrowings before adjusting for unamortized discount and fair value adjustment	8,056		6,206
Debt instrument, stated interest rate percentage (as a percent)	3.34%
1.88% Notes and Debentures, maturing in 2022
Debt Disclosure
Aggregate carrying amount of long-term borrowings before adjusting for unamortized discount and fair value adjustment	1,000		1,000
Debt instrument, stated interest rate percentage (as a percent)	1.88%
3.38% Notes and Debentures, maturing in 2023
Debt Disclosure
Aggregate carrying amount of long-term borrowings before adjusting for unamortized discount and fair value adjustment	1,500		1,500
Debt instrument, stated interest rate percentage (as a percent)	3.38%
3.63% Notes and Debentures, maturing in 2024
Debt Disclosure
Aggregate carrying amount of long-term borrowings before adjusting for unamortized discount and fair value adjustment	2,000
Debt instrument, stated interest rate percentage (as a percent)	3.63%
7.00% Notes and Debentures, maturing in 2025
Debt Disclosure
Aggregate carrying amount of long-term borrowings before adjusting for unamortized discount and fair value adjustment	600		600
Debt instrument, stated interest rate percentage (as a percent)	7.00%
6.22% Notes and Debentures, maturing in 2027
Debt Disclosure
Aggregate carrying amount of long-term borrowings before adjusting for unamortized discount and fair value adjustment	469		469
Debt instrument, stated interest rate percentage (as a percent)	6.22%
6.50% Notes and Debentures, maturing in 2028
Debt Disclosure
Aggregate carrying amount of long-term borrowings before adjusting for unamortized discount and fair value adjustment	313		313
Debt instrument, stated interest rate percentage (as a percent)	6.50%
5.88% Notes and Debentures, maturing in 2032
Debt Disclosure
Aggregate carrying amount of long-term borrowings before adjusting for unamortized discount and fair value adjustment	600		600
Debt instrument, stated interest rate percentage (as a percent)	5.88%
8.00% Notes and Debentures, maturing in 2038
Debt Disclosure
Aggregate carrying amount of long-term borrowings before adjusting for unamortized discount and fair value adjustment	83		83
Debt instrument, stated interest rate percentage (as a percent)	8.00%
5.60% Notes and Debentures, maturing in 2039
Debt Disclosure
Aggregate carrying amount of long-term borrowings before adjusting for unamortized discount and fair value adjustment	745		745
Debt instrument, stated interest rate percentage (as a percent)	5.60%
4.00% Notes and Debentures, maturing in 2042
Debt Disclosure
Aggregate carrying amount of long-term borrowings before adjusting for unamortized discount and fair value adjustment	1,107		1,107
Debt instrument, stated interest rate percentage (as a percent)	4.00%
7.00% Notes and Debentures, maturing in 2045
Debt Disclosure
Aggregate carrying amount of long-term borrowings before adjusting for unamortized discount and fair value adjustment	27		27
Debt instrument, stated interest rate percentage (as a percent)	7.00%
7.13% Notes and Debentures, maturing in 2096
Debt Disclosure
Aggregate carrying amount of long-term borrowings before adjusting for unamortized discount and fair value adjustment	316		316
Debt instrument, stated interest rate percentage (as a percent)	7.13%
2.0% Euros maturing in 2015 - 2025
Debt Disclosure
Aggregate carrying amount of long-term borrowings before adjusting for unamortized discount and fair value adjustment	4,815		5,894
Debt instrument, stated interest rate percentage (as a percent)	2.00%
2.75% Pound sterling maturing in 2017 - 2020
Debt Disclosure
Aggregate carrying amount of long-term borrowings before adjusting for unamortized discount and fair value adjustment	1,293		1,254
Debt instrument, stated interest rate percentage (as a percent)	2.75%
0.5% Japanese yen maturing in 2017
Debt Disclosure
Aggregate carrying amount of long-term borrowings before adjusting for unamortized discount and fair value adjustment	867		1,057
Debt instrument, stated interest rate percentage (as a percent)	0.50%
3.8% Swiss francs maturing in 2015-2020
Debt Disclosure
Aggregate carrying amount of long-term borrowings before adjusting for unamortized discount and fair value adjustment	181		181
Debt instrument, stated interest rate percentage (as a percent)	3.80%
2.2% Canadian Maturing 2017
Debt Disclosure
Aggregate carrying amount of long-term borrowings before adjusting for unamortized discount and fair value adjustment	469		471
Debt instrument, stated interest rate percentage (as a percent)	2.20%
9.06% Other maturing in 2015-2018
Debt Disclosure
Aggregate carrying amount of long-term borrowings before adjusting for unamortized discount and fair value adjustment	$ 350		$ 291
Debt instrument, stated interest rate percentage (as a percent)	9.06%

[1] The portion of the company’s fixed-rate debt obligations that is hedged is reflected in the ConsolidatedStatement of Financial Position as an amount equal to the sum of the debt’s carrying value plus a fair value adjustment representing changes in the fair value of the hedged debt obligations attributable to movements in benchmark interest rates.