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Description of Business and Summary of Significant Accounting Policies - Our Business (Details) (USD $)
In Millions, unless otherwise specified |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
|
Sep. 30, 2014
continent
country
|
Sep. 30, 2013
|
Sep. 30, 2014
Segment
continent
country
|
Sep. 30, 2013
|
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| Concentration Risk [Line Items] | ||||
| Number of reportable segments | 1 | |||
| Number of countries in which entity operates | 18 | 18 | ||
| Number of continents in which entity operates | 4 | 4 | ||
| Revenues from four largest contracts | $ 301 | $ 349 | $ 918 | $ 1,185 |
| Increase in operating income due to cumulative catch up adjustments | 3 | 29 | 30 | 106 |
|
U.S. Army | Revenue | Government Contracts Concentration Risk
|
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| Concentration Risk [Line Items] | ||||
| Concentration percentage | 87.00% | |||
|
Four Largest Contracts | U.S. Army | Revenue | Government Contracts Concentration Risk
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| Concentration Risk [Line Items] | ||||
| Concentration percentage | 67.00% | |||
| Revenues from four largest contracts | 619 | |||
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Contracts Accounted for under Percentage of Completion
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| Concentration Risk [Line Items] | ||||
| Increase in operating income due to cumulative catch up adjustments | $ 5 | $ 39 | ||