Employee Benefit Plans - Additional Information (Details) $ in Millions	12 Months Ended
Dec. 31, 2020 USD ($) plan	Dec. 31, 2019 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Number of pension plans \| plan	2
Estimated contributions in the next fiscal year	$ 9
Defined Benefit Plan, Accumulated Benefit Obligation	180	$ 154
Underfunded status of Pension Plans	$ 32	$ 25
U.K. Plan
Defined Benefit Plan Disclosure [Line Items]
Maximum increase in pensionable earnings	2.00%
Funded percentage (less than)	100.00%
U.K. Plan \| Global return fund
Defined Benefit Plan Disclosure [Line Items]
Target allocation in debt securities	37.00%
U.K. Plan \| Real estate
Defined Benefit Plan Disclosure [Line Items]
Target allocation in debt securities	10.00%
U.K. Plan \| Liability Driven Investments
Defined Benefit Plan Disclosure [Line Items]
Target allocation in debt securities	20.00%
U.K. Plan \| Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Target allocation in debt securities	13.00%
U.K. Plan \| U.K \| Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation in debt securities	4.00%
U.K. Plan \| Other Than United Kingdom \| Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation in debt securities	16.00%
Canadian Plan \| Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Target allocation in debt securities	33.00%
Canadian Plan \| Canada \| Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation in debt securities	23.00%
Canadian Plan \| Other Than Canada \| Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation in debt securities	44.00%

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Defined Benefit Plan, Plan Amendments, Maximum Annual Increase for Pensionable Earnings While Plan is Not 100 Percent Funded

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Amount of actuarial present value of benefits attributed to employee service rendered, excluding assumptions about future compensation level.

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Amount of contribution expected to be received by defined benefit plan from employer in next fiscal year following current fiscal year.

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Percentage of plan assets to benefit obligation of defined benefit plan.

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Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

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Amount of liability, recognized in statement of financial position, for defined benefit pension and other postretirement plans, classified as noncurrent.

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