Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee.

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Name:	us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Employee Benefit Plans - Schedule of Fair Value of Plan Assets Measured on a Recurring Basis (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Assets in fair value hierarchy		$ 252
Level 2 \| Corporate bonds and government securities
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocation percentage		40.00%
Net Asset Value Per Share \| Common collective trusts
Defined Benefit Plan Disclosure [Line Items]
Assets in fair value hierarchy	$ 224
Plan asset allocation percentage		60.00%