Commitments and Contingencies (Unaudited) (Tables)

3 Months Ended

Mar. 31, 2018

Environmental Remediation Range of Future Costs [Line Items]

Environmental Remediation [Table Text Block]

The table below summarizes management’s estimate of the range of reasonably possible future costs for environmental remediation, the amount accrued within that range, and the deferred costs expected to be recoverable through overhead charges on U.S. Government contracts as of March 31, 2018 and December 31, 2017:

$ in millions	Range of Reasonably Possible Future Costs(1)	Accrued Costs(2)		Deferred Costs(3)
March 31, 2018	$410 - $789	$	416	$	211
December 31, 2017	405 - 792	410		207

⁽¹⁾  Estimated remediation costs are not discounted to present value. The range of reasonably possible future costs does not take into consideration amounts expected to be recoverable through overhead charges on U.S. Government contracts.

⁽²⁾ As of March 31, 2018, $151 million is recorded in other current liabilities and $265 million is recorded in other non-current liabilities.

⁽³⁾ As of March 31, 2018, $79 million is deferred in prepaid expenses and other current assets and $132 million is deferred in other non-current assets. These amounts are evaluated for recoverability on a routine basis.