Fair Value of Financial Investments - Financial Investments (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Fair value of financial investments and liabilities
Total financial investments	$ 36	$ 48
Prepaid expenses and other \| Auction rate securities
Fair value of financial investments and liabilities
Available-for-sale securities, debt securities, current	12	0
Other assets \| Auction rate securities
Fair value of financial investments and liabilities
Recurring investments, available-for-sale securities	0	22
Other assets \| Equity method investments
Fair value of financial investments and liabilities
Equity method investments	14	13
Other assets \| Private equity funds
Fair value of financial investments and liabilities
Non-recurring investments	7	10
Other assets \| Other investments
Fair value of financial investments and liabilities
Non-recurring investments	$ 3	$ 3

Amount of investments in debt securities classified as available-for-sale, expected to be converted to cash, sold or exchanged within one year or the normal operating cycle, if longer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=65884222&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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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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Amount, after adjustment, of cost-method investment. Adjustments include, but are not limited to, dividends received in excess of earnings after date of investment that are considered a return of investment and other than temporary impairments.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

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Reference 9: http://www.xbrl.org/2003/role/presentationRef
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