Fair Value Fair Value Inputs Assets Quantitative Information (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014
Venture Capital Funds [Member] \| Market Approach Valuation Technique [Member] \| Comparable Companies [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	260
Venture Capital Funds [Member] \| Market Approach Valuation Technique [Member] \| Recent Transactions [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	50
Minimum [Member] \| Comparable Companies [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Revenue Multiple	1.0
Fair Value Inputs, Earnings before Interest, Taxes, Depreciation, and Amortization Multiple	8.0
Maximum [Member] \| Comparable Companies [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Revenue Multiple	6.0
Fair Value Inputs, Earnings before Interest, Taxes, Depreciation, and Amortization Multiple	10.0
Unobservable Inputs (Level 3) [Member] \| Equity Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	310

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

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Market valuation of entity divided by earnings before interest, taxes, depreciation, and amortization (EBITDA), used as an input to measure fair value.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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Market valuation of entity divided by revenue, used as an input to measure fair value.

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