Investments - Other Investments (Details) $ in Billions	1 Months Ended
Apr. 30, 2020 USD ($) preferred_stock_series
Schedule of Other Investments [Line Items]
Cash payments for the redemption of redeemable preferred shares \| $	$ 1.8
Air Touch
Schedule of Other Investments [Line Items]
Number of series of preferred stock \| preferred_stock_series	3
Air Touch
Schedule of Other Investments [Line Items]
Number of series of preferred stock \| preferred_stock_series	2
Cash payments received upon redemption of preferred stock \| $	$ 1.7

The cash inflow associated with the maturity, prepayments and calls (requests for early payments) of debt securities designated as held-to-maturity.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3179-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=124260329&loc=d3e26853-111562

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