Fair Value Of Financial Instruments (Redemption Of The Plan's Level 3 Investments) (Details) - Interest in Limited Partnerships and Limited Liability Corporations [Member] $ in Millions	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 162	$ 156	$ 165
E. Casino Road, LLC (Member)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 18
E. Casino Road, LLC (Member) | Measurement Input, Cap Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Capitalization Rate	7.00
Comm Drive, LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 10
Comm Drive, LLC [Member] | Measurement Input, Cap Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Capitalization Rate	8.25
CTE Drive, LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 12
CTE Drive, LLC [Member] | Measurement Input, Cap Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Capitalization Rate	9.75
Oakbrook Parkway LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 28
Oakbrook Parkway LLC [Member] | Measurement Input, Cap Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Capitalization Rate	7.50
West Jefferson, LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 24
West Jefferson, LLC [Member] | Measurement Input, Cap Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Capitalization Rate	9.00
MacCorkle Ave SE, LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 14
MacCorkle Ave SE, LLC [Member] | Measurement Input, Cap Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Capitalization Rate	9.25
S. Pike Road West, LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 1
S. Pike Road West, LLC [Member] | Measurement Input, Cap Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Capitalization Rate	9.00
N. US 131, LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 1
N. US 131, LLC [Member] | Measurement Input, Cap Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Capitalization Rate	9.50
E. Stockton Blvd, LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 7
E. Stockton Blvd, LLC [Member] | Measurement Input, Cap Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Capitalization Rate	7.75
E. Lime Street, LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 10
E. Lime Street, LLC [Member] | Measurement Input, Cap Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Capitalization Rate	9.00
N. Morgan Street, LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 37
N. Morgan Street, LLC [Member] | Measurement Input, Cap Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Capitalization Rate	8.50