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Dispositions (Narrative) (Details) $ in Millions		1 Months Ended		3 Months Ended			9 Months Ended
Dispositions (Narrative) (Details) $ in Millions	Jul. 24, 2015 USD ($) extension	Feb. 28, 2015 USD ($)	Jan. 30, 2015 USD ($)	Oct. 02, 2015 USD ($)	Oct. 31, 2014 USD ($)	May. 02, 2014 USD ($)	Oct. 02, 2015 USD ($)	Oct. 31, 2014 USD ($)	Oct. 31, 2013 MW
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Note receivable							$ 73	$ 0
Emergency Management Consulting
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net proceeds from divestures					$ 19
Other Disposals
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment of assets						$ 12
Cloudshield Technologies
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net proceeds from divestures		$ 5
Plainfield
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of ownership									100.00%
Capacity of power plant \| MW									37.5
Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash consideration received	$ 29
Discontinued Operations, Held-for-sale \| Plainfield
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Aggregate consideration	101
Note receivable	72
Maximum earn-out payment	$ 30
Number of extensions \| extension	3
Stated interest rate	6.00%
Interest rate, If maturity is extended beyond July 24, 2017	8.00%
Interest rate, If maturity is extended beyond July 24, 2019	9.00%
Impairment of assets				$ 29
Health and Engineering \| Discontinued Operations, Held-for-sale \| Plainfield
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment of assets			$ 40
Fixed Asset and Inventory \| Other Disposals
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment of assets						$ 9