FINANCIAL INSTRUMENTS - Debt and Equity Securities (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Debt and Marketable Equity Securities
Debt securities - noncurrent, Adjusted Cost		$ 8	$ 5
Debt securities - noncurrent, Gross Unrealized Gains		3	3
Debt securities - noncurrent, Fair Value		11	8
Available-for-sale equity investments, Adjusted Cost		1	3
Available-for-sale equity investments, Gross Unrealized Gains		3	5
Available-for-sale equity investments, Gross Unrealized Losses		0	0
Available-for-sale equity investments, Fair Value		4	7
Sales of debt and available-for-sale equity investments
Proceeds		7	151	$ 8
Gross realized gains (before taxes)		3	3	1
Gross realized losses (before taxes)		2	37	1
Unrealized holding gains/(losses) on available-for-sale debt and marketable equity securities
Net unrealized gains/(losses) arising during the period		0	(23)
Net unrealized (gains)/losses reclassified to net income		1	21
Writedowns included in net income for the period		$ 0	$ 0
Maximum contractual maturities of substantially all available-for-sale debt securities		1 year
Lenovo's common stock
Debt and Marketable Equity Securities
Available-for-sale equity investments, Adjusted Cost				185
Other-than-temporary impairment loss				$ 86
Sales of debt and available-for-sale equity investments
Gross realized losses (before taxes)	$ 37

This describes the maximum time frame of the contract terms of the entity's available-for-sale debt securities.

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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale.

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This item represents the cost of debt securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in equity securities classified as available-for-sale.

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in equity securities classified as available-for-sale.

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This item represents the cost of equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments for other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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Total of debt securities categorized neither as held-to-maturity nor trading which are intended be sold or mature more than one year from the balance sheet date or operating cycle, if longer.

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Equity securities categorized neither as held-to-maturity nor trading which are intended be sold more than one year from the balance sheet date or operating cycle, if longer.

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This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

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The total amount of proceeds received for the sale of securities, categorized neither as held-to-maturity nor trading securities, during the reporting period.

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This item represents the gross loss realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

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Amount after tax of reclassification adjustment from accumulated other comprehensive income for unrealized gain (loss) realized upon the sale of available-for-sale securities.

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Amount after tax of reclassification adjustment from accumulated other comprehensive income for unrealized loss realized upon the write-down of available-for-sale securities.

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Amount after tax, before reclassification adjustments, of unrealized holding gain (loss) on available-for-sale securities.

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The amount of other than temporary impairment losses on investments in debt and equity securities categorized as Available-for-sale which have been recognized in earnings during the period. Such impairment losses consist of other than temporary impairments (OTTI) on equity securities, credit losses on investments in debt securities, and when the entity intends to sell an impaired debt security or it is more likely than not that the entity will be required to sell the impaired debt security before recovery of its amortized cost basis.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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