Leases (Summary of Operating Lease Liabilities) (Parenthetical) (Details) $ in Millions	Dec. 31, 2019 USD ($)
Office Facility
Lessee Lease Description [Line Items]
Total lease payments for an operating lease that has not yet commenced	$ 55

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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Balance Type:	na
Period Type:	duration