Commitments, Contingencies and Guarantees - Related Party Letter Agreement (Details) - 28 Associates LLC - USD ($) $ in Millions	9 Months Ended
Sep. 30, 2019	Mar. 27, 2019
Chairman
Related Party Transaction [Line Items]
Ownership interest		50.00%
Scenario, Forecast \| Related Party Letter Agreement
Related Party Transaction [Line Items]
Potential break-up fee	$ 6

Expenses recognized resulting from transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

Name:	us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration