Income Taxes (Narrative) (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($)
Investments Owned Federal Income Tax Note [Line Items]
Increase Decrease in Income Tax Expense	$ 38
Income tax examination, description	The statute is closed for IRS examination of years prior to 2013. The IRS is currently examining DESC’s federal returns from 2013 through 2017. DESC is no longer subject to state and local income tax examinations by tax authorities for years prior to 2019.
Decrease in Unrecognized Tax Benefits is Reasonably Possible	$ 39
Potential increase in earnings in next twelve months if tax benefits recognized	$ 26
Earliest Tax Year | Federal | IRS
Investments Owned Federal Income Tax Note [Line Items]
Income tax examination, year under examination	2013
Latest Tax Year | Federal | IRS
Investments Owned Federal Income Tax Note [Line Items]
Income tax examination, year under examination	2017