Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2020

Commitments and Contingencies Disclosure [Abstract]

Environmental Remediation [Table Text Block]

The table below summarizes the amount accrued for environmental remediation costs, management’s estimate of the amount of reasonably possible future costs in excess of accrued costs and the deferred costs expected to be recoverable through overhead charges on U.S. government contracts as of December 31, 2020 and 2019:

$ in millions	Accrued Costs(1)(2)		Reasonably Possible Future Costs in excess of Accrued Costs(2)		Deferred Costs(3)
December 31, 2020	$	614	$	346	$	529
December 31, 2019	531		448		436

(1)As of December 31, 2020, $237 million is recorded in Other current liabilities and $377 million is recorded in Other non-current liabilities.

(2)Estimated remediation costs are not discounted to present value. The reasonably possible future costs in excess of accrued costs do not take into consideration amounts expected to be recoverable through overhead charges on U.S. government contracts.

(3)As of December 31, 2020, $210 million is deferred in Prepaid expenses and other current assets and $319 million is deferred in Other non-current assets. These amounts are evaluated for recoverability on a routine basis.