Employee Retirement and Severance Benefits - Additional Information (Detail) (JPY ¥) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Employee Benefits Disclosure [Line Items]
Defined contribution pension plans	¥ 12,511	¥ 11,780	¥ 9,148
Japanese Plans
Employee Benefits Disclosure [Line Items]
Invested in equity securities	30.00%	30.00%
Invested in debt securities	50.00%	50.00%
Fair Value of other assets	448,736	460,090	457,208
Contribution in defined benefit pension plan	21,946
Japanese Plans \| Fair Value, Inputs, Level 3
Employee Benefits Disclosure [Line Items]
Fair Value of other assets	1,147	1,039
Japanese Plans \| Life insurance
Employee Benefits Disclosure [Line Items]
Invested in other plan assets	20.00%	20.00%
Foreign Plans
Employee Benefits Disclosure [Line Items]
Invested in equity securities	40.00%	40.00%
Invested in debt securities	55.00%	55.00%
Fair Value of other assets	192,033	197,835	75,058
Contribution in defined benefit pension plan	¥ 8,931
Foreign Plans \| Real estate assets
Employee Benefits Disclosure [Line Items]
Invested in other plan assets	5.00%	5.00%

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The employer's best estimate, as soon as it can be reasonably determined, of contributions expected to be paid to the plan during the next fiscal year beginning after the date of the latest statement of financial position. Estimated contributions may be presented in the aggregate combining (1) contributions required by funding regulations or laws, (2) discretionary contributions, and (3) noncash contributions.

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Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets.

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Target allocation percentage of investments in debt securities to total plan assets presented on a weighted-average basis as of the measurement date of the latest statement of financial position.

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Target allocation percentage of investments in equity securities to total plan assets presented on a weighted-average basis as of the measurement date of the latest statement of financial position.

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Target allocation percentage in other than debt securities, equity securities, and real estate to total plan assets presented on a weighted-average basis as of the measurement date of the latest statement of financial position.

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The amount of the cost recognized during the period for defined contribution plans.

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