Retirement Benefits (Schedule of Allocation of Plan Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
DB Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Plan assets	$ 2,964	$ 3,004	$ 2,820
DB Pension Plans | Plan Assets Excluding Pooled Funds
Defined Benefit Plan Disclosure [Line Items]
Plan assets	148	225
DB Pension Plans | Plan Assets Excluding Pooled Funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets	148	225
DB Pension Plans | Plan Assets Excluding Pooled Funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0	0
DB Pension Plans | Cash and short-term investments
Defined Benefit Plan Disclosure [Line Items]
Plan assets	148	178
DB Pension Plans | Cash and short-term investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets	148	178
DB Pension Plans | Cash and short-term investments | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0	0
DB Pension Plans | Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0	47
DB Pension Plans | Mutual funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0	47
DB Pension Plans | Mutual funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0	0
DB Pension Plans | Pooled funds
Defined Benefit Plan Disclosure [Line Items]
Plan assets	2,816	2,779
OPEB Plan
Defined Benefit Plan Disclosure [Line Items]
Plan assets	1,588	1,559	$ 1,446
OPEB Plan | Plan Assets Excluding Pooled Funds
Defined Benefit Plan Disclosure [Line Items]
Plan assets	356	402
OPEB Plan | Plan Assets Excluding Pooled Funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets	258	303
OPEB Plan | Plan Assets Excluding Pooled Funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets	98	99
OPEB Plan | Cash and short-term investments
Defined Benefit Plan Disclosure [Line Items]
Plan assets	35	82
OPEB Plan | Cash and short-term investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets	35	82
OPEB Plan | Cash and short-term investments | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0	0
OPEB Plan | U.S. government and agencies securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets	13	16
OPEB Plan | U.S. government and agencies securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0	0
OPEB Plan | U.S. government and agencies securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets	13	16
OPEB Plan | Corporate debt
Defined Benefit Plan Disclosure [Line Items]
Plan assets	68	67
OPEB Plan | Corporate debt | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0	0
OPEB Plan | Corporate debt | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets	68	67
OPEB Plan | State and municipal bonds
Defined Benefit Plan Disclosure [Line Items]
Plan assets	2	1
OPEB Plan | State and municipal bonds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0	0
OPEB Plan | State and municipal bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets	2	1
OPEB Plan | Foreign bonds
Defined Benefit Plan Disclosure [Line Items]
Plan assets	15	15
OPEB Plan | Foreign bonds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0	0
OPEB Plan | Foreign bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets	15	15
OPEB Plan | Common stocks
Defined Benefit Plan Disclosure [Line Items]
Plan assets	170	161
OPEB Plan | Common stocks | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets	170	161
OPEB Plan | Common stocks | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0	0
OPEB Plan | Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Plan assets	53	60
OPEB Plan | Mutual funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets	53	60
OPEB Plan | Mutual funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0	0
OPEB Plan | Pooled funds
Defined Benefit Plan Disclosure [Line Items]
Plan assets	$ 1,232	$ 1,157