Employee Benefits - Additional Information (Details) $ in Millions	Dec. 31, 2019 USD ($)
UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Estimate of contributions to defined benefit pension plans for the current fiscal year	$ 99
U.K.
Defined Benefit Plan Disclosure [Line Items]
Estimate of contributions to defined benefit pension plans for the current fiscal year	5
Other
Defined Benefit Plan Disclosure [Line Items]
Estimate of contributions to defined benefit pension plans for the current fiscal year	$ 19