Variable Interest Entities - Narrative (Details) - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Variable Interest Entities
Assets	$ 18,042,447,000	$ 18,287,013,000
Liabilities	10,394,622,000	10,087,120,000
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entities
Assets	217,103,000	217,451,000
Variable Interest Entity, Primary Beneficiary
Variable Interest Entities
Assets	5,089,516,000	4,923,656,000
Liabilities	$ 2,811,319,000	$ 2,646,623,000