Accounts Receivable (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable Sales	$ 3,401		$ 3,699		$ 3,218
Amounts billed or billable	113		152
Billable contracts receivable to be invoiced in the subsequent month	1,054		1,049
Deferred proceeds	486		639		386
Loss on sale of accounts receivables	17		21		20
Estimated (decrease) increase to operating cash flows	(55)	[1]	(78)	[1]	133	[1]
Accounts Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amounts billed or billable	2,651		2,639
Unbilled amounts	390		335
Allowance for doubtful accounts	(112)		(108)
Accounts Receivable, Net	$ 2,929		$ 2,866

[1] Represents the difference between current and prior year fourth quarter receivable sales adjusted for the effects of: (i) the deferred proceeds, (ii) collections prior to the end of the year and (iii) currency.