CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities
Net income (loss)	$ 1,977,820	$ (1,768,407)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities
Amortization of premiums and discounts of investments, net	555,659	1,130,285
Amortization of securitized debt premiums and discounts and deferred financing costs	(4,129)	(7,263)
Depreciation, amortization and other noncash expenses	21,084	28,181
Net (gains) losses on disposal of investments and other	37,561	(652,150)
Net (gains) losses on investments and derivatives	(1,088,608)	2,889,963
Net (gains) losses on business divestitures	262,045	0
Income from unconsolidated joint ventures	5,889	(2,596)
Loan loss provision (reversal)	(145,260)	146,084
Payments on purchases of loans held for sale	(51,403)	(120,855)
Proceeds from sales and repayments of loans held for sale	88,050	139,672
Net receipts (payments) on derivatives	608,184	(2,210,881)
Net change in
Other assets	22,441	291,745
Interest receivable	34,881	148,165
Interest payable	(81,183)	(320,997)
Other liabilities	(27,750)	(30,769)
Net cash provided by (used in) operating activities	2,215,281	(339,823)
Cash flows from investing activities
Payments on purchases of securities	(18,334,872)	(24,970,238)
Proceeds from sales of securities	11,146,996	50,295,038
Principal payments on securities	14,638,456	14,392,160
Payments on purchases and origination of loans	(4,710,425)	(1,658,578)
Proceeds from sales of loans	879,147	583,040
Principal payments on loans	2,016,373	1,558,859
Payments on purchases of MSR	(416,149)	0
Proceeds from sales of MSR	376	0
Payments on purchases of interests in MSR	(53,034)	0
Investments in real estate	(1,815)	(6,123)
Proceeds from sales of real estate	53,910	0
Proceeds from reverse repurchase agreements	15,184,313	46,100,000
Payments on reverse repurchase agreements	(15,184,313)	(46,100,000)
Distributions in excess of cumulative earnings from unconsolidated joint ventures	290	6,641
Proceeds from sale of equity securities	6,957	0
Cash acquired in asset acquisition	0	1,047
Net proceeds from business divestiture	1,118,100	0
Net cash provided by (used in) investing activities	6,344,310	40,201,846
Cash flows from financing activities
Proceeds from repurchase agreements and other secured financing	1,702,497,310	2,353,694,509
Payments on repurchase agreements and other secured financing	(1,712,035,449)	(2,394,417,060)
Proceeds from issuances of securitized debt	2,005,080	2,385,374
Principal payments on securitized debt	(1,270,367)	(860,306)
Payment of deferred financing cost	0	(553)
Net proceeds from stock offerings, direct purchases and dividend reinvestments	469,334	1,075
Proceeds from participations issued	1,036,800	0
Payments on repurchases of participations issued	(434,873)	0
Principal payments on participations issued	(10,420)	0
Net principal receipts (payments) on mortgages payable	(1,019)	22,550
Net contributions (distributions) from (to) noncontrolling interests	3,180	8,167
Net payment on share repurchase	0	(175,076)
Settlement of stock-based awards in satisfaction of withholding tax requirements	(2,773)	0
Dividends paid	(1,013,797)	(1,131,450)
Net cash provided by (used in) financing activities	(8,756,994)	(40,472,770)
Net (decrease) increase in cash and cash equivalents	(197,403)	(610,747)
Cash and cash equivalents including cash pledged as collateral, beginning of period	1,243,703	1,850,729
Cash and cash equivalents including cash pledged as collateral, end of period	1,046,300	1,239,982
Supplemental disclosure of cash flow information
Interest received	2,107,854	2,926,598
Dividends received	51	4,485
Interest paid (excluding interest paid on interest rate swaps)	228,875	1,050,203
Net interest paid on interest rate swaps	258,061	290,277
Taxes received (paid)	780	1,551
Noncash investing and financing activities
Receivable for unsettled trades	42,482	54,200
Payable for unsettled trades	571,540	1,176,001
Net change in unrealized gains (losses) on available-for-sale securities, net of reclassification adjustment	(1,735,697)	1,450,865
Dividends declared, not yet paid	318,986	308,644
Derecognition of assets of consolidated VIEs	3,052,280	1,222,221
Derecognition of securitized debt of consolidated VIEs	2,496,118	1,141,311
Derecognition of mortage payable of consolidated VIEs	$ 314,485	$ 0