Retirement Benefits - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Compensation and Retirement Disclosure [Line Items]
Portion of pension and OPEB obligation attributed to disclosed plans (as a percent)			99.00%
Defined contribution plan, employer contribution	$ 38	$ 39	$ 80	$ 82
Pension Plan [Member] | United States [Member]
Compensation and Retirement Disclosure [Line Items]
Defined benefit pension plans, employer contributions			0
Defined benefit plan, estimated future employer additional contributions, remainder of fiscal year	0		0
Pension Plan [Member] | United Kingdom [Member]
Compensation and Retirement Disclosure [Line Items]
Defined benefit pension plans, employer contributions			16
Defined benefit plan, estimated future employer additional contributions, remainder of fiscal year	23		23
Pension Plan [Member] | Other Foreign Plans [Member]
Compensation and Retirement Disclosure [Line Items]
Defined benefit pension plans, employer contributions			18
Defined benefit plan, estimated future employer additional contributions, remainder of fiscal year	$ 6		$ 6