Contingencies and Commitments - Performance Claims under Contracts (Details 3) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2013
Recognized claims against clients
Contracts receivable, claims and uncertain amounts	$ 30	$ 21

Amount of billed or unbilled claims or other similar items subject to uncertainty concerning their determination or ultimate realization under long-term contracts.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.3(c)(3))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_ContractsReceivableClaimsAndUncertainAmounts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant