Retirement Benefit Plans - Obligations and Funded Status (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) benefitPlan	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Fair value of plan assets
Fair value of plan assets, beginning of period	$ 405
Benefits paid:
Fair value of plan assets, end of period	$ 383	$ 405
Number of underfunded benefit plans | benefitPlan	3
Pension Plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Projected benefit obligation, beginning of period	$ 401	364	$ 320
Interest cost	7	10	12
Actuarial loss (gain)	(18)	42	47
Benefits paid:
Plan assets	(16)	(15)	(15)
Projected benefit obligation, end of period	374	401	364
Fair value of plan assets
Fair value of plan assets, beginning of period	405	363	308
Actual return on plan assets, net of expenses	(7)	56	69
Company contributions	1	1	1
Benefits paid:
Plan assets	(16)	(15)	(15)
Fair value of plan assets, end of period	383	405	363
Funded status, end of period	9	4	(1)
Other assets recognized in the consolidated balance sheet	9	4
Other liabilities recognized in the consolidated balance sheet			(1)
Pretax net gain recognized in accumulated other comprehensive income (loss)	2	3	4
Projected benefit obligation in excess of plan assets	$ 13	$ 14	$ 13