Retirement Benefits - Benefit Obligations and Plan Assets in Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Other current liabilities	$ 47	$ 20
Pension obligations	1,109	2,051
Non-pension postretirement benefit obligations	0	0
Unfunded status (net benefit obligation less plan assets)	1,156	2,071
Other Postretirement Benefit Plan, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Other current liabilities	26	26
Pension obligations	0	0
Non-pension postretirement benefit obligations	507	811
Unfunded status (net benefit obligation less plan assets)	$ 533	$ 837