Pension and Other Postretirement Benefits - Narrative (Details) £ in Millions, $ in Millions	3 Months Ended	6 Months Ended		12 Months Ended
	Dec. 31, 2021 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2022 GBP (£)	Dec. 31, 2022 USD ($)	Dec. 31, 2022 GBP (£)
Defined Benefit Plan Disclosure [Line Items]
Employer contributions		$ 92	£ 71
Settlement charge	$ 1,511
Forecast
Defined Benefit Plan Disclosure [Line Items]
Employer contributions				$ 154	£ 127