Fair Value Measurements and Financial Instruments - Schedule of assets and liabilities that are measured at fair value on a recurring basis (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013
Fair Value Disclosures [Abstract]
Net assets value (in dollar per share)	$ 1
Money market funds and highly liquid debt securities [Member] | Recurring [Member]
Assets:
Money market funds and highly liquid debt securities	$ 1,850	[1]	$ 2,079	[2]
Corporate bonds [Member] | Recurring [Member]
Assets:
Other investments	1		2
Government bonds [Member] | Recurring [Member]
Assets:
Other investments	6		7
Equity securities [Member] | Recurring [Member]
Assets:
Other investments	11		13
Interest rate contracts [Member] | Recurring [Member]
Assets:
Derivatives	0		9
Foreign exchange contracts [Member] | Recurring [Member]
Assets:
Derivatives	46		71
Liabilities:
Derivatives	58		93
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Money market funds and highly liquid debt securities [Member] | Recurring [Member]
Assets:
Money market funds and highly liquid debt securities	1,850	[1]	2,054	[2]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Corporate bonds [Member] | Recurring [Member]
Assets:
Other investments	0		0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Government bonds [Member] | Recurring [Member]
Assets:
Other investments	0		0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity securities [Member] | Recurring [Member]
Assets:
Other investments	6		6
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Interest rate contracts [Member] | Recurring [Member]
Assets:
Derivatives	0		0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Foreign exchange contracts [Member] | Recurring [Member]
Assets:
Derivatives	0		0
Liabilities:
Derivatives	0		0
Significant Other Observable Inputs (Level 2) [Member] | Money market funds and highly liquid debt securities [Member] | Recurring [Member]
Assets:
Money market funds and highly liquid debt securities	0	[1]	25	[2]
Significant Other Observable Inputs (Level 2) [Member] | Corporate bonds [Member] | Recurring [Member]
Assets:
Other investments	0		0
Significant Other Observable Inputs (Level 2) [Member] | Government bonds [Member] | Recurring [Member]
Assets:
Other investments	6		7
Significant Other Observable Inputs (Level 2) [Member] | Equity securities [Member] | Recurring [Member]
Assets:
Other investments	5		7
Significant Other Observable Inputs (Level 2) [Member] | Interest rate contracts [Member] | Recurring [Member]
Assets:
Derivatives	0		9
Significant Other Observable Inputs (Level 2) [Member] | Foreign exchange contracts [Member] | Recurring [Member]
Assets:
Derivatives	46		71
Liabilities:
Derivatives	58		93
Significant Unobservable Inputs (Level 3) [Member] | Money market funds and highly liquid debt securities [Member] | Recurring [Member]
Assets:
Money market funds and highly liquid debt securities	0	[1]	0	[2]
Significant Unobservable Inputs (Level 3) [Member] | Corporate bonds [Member] | Recurring [Member]
Assets:
Other investments	1		2
Significant Unobservable Inputs (Level 3) [Member] | Government bonds [Member] | Recurring [Member]
Assets:
Other investments	0		0
Significant Unobservable Inputs (Level 3) [Member] | Equity securities [Member] | Recurring [Member]
Assets:
Other investments	0		0
Significant Unobservable Inputs (Level 3) [Member] | Interest rate contracts [Member] | Recurring [Member]
Assets:
Derivatives	0		0
Significant Unobservable Inputs (Level 3) [Member] | Foreign exchange contracts [Member] | Recurring [Member]
Assets:
Derivatives	0		0
Liabilities:
Derivatives	$ 0		$ 0

[1] Includes $1,850 million of money market funds that are classified as Fiduciary assets, Short-term investments or Cash and cash equivalents in the Consolidated Statements of Financial Position, depending on their nature and initial maturity. See Note 7 "Investments" for additional information regarding the Company's investments.

[2] Includes $2,054 million of money market funds and $25 million of highly liquid debt securities that are classified as Fiduciary assets, Short-term investments or Cash and cash equivalents in the Consolidated Statements of Financial Position, depending on their nature and initial maturity. See Note 7 "Investments" for additional information regarding the Company's investments.