Retirement Benefits Pension Plan Contributions (Details) - Pension Plan $ in Millions	9 Months Ended
	Sep. 30, 2023 USD ($)
Funded Plan
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 424
Unfunded Plan
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year	400
Defined Benefit Plan, Plan Assets, Contributions by Employer	301
Minimum | Funded Plan
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year	500
Maximum | Funded Plan
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year	$ 600