Fair Value Fair Value Inputs Assets Quantitative Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014
Venture Capital Funds [Member] | Market Approach Valuation Technique [Member] | Comparable Companies [Member]
Available-for-sale Securities	$ 273
Venture Capital Funds [Member] | Market Approach Valuation Technique [Member] | Recent Transactions [Member]
Available-for-sale Securities	40
Minimum [Member] | Comparable Companies [Member]
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, Revenue Multiple	6.0
Fair Value Inputs, Earnings before Interest, Taxes, Depreciation, and Amortization Multiple	9.0
Unobservable Inputs (Level 3) [Member] | Equity Securities [Member]
Available-for-sale Securities	$ 313