Mortgage Loans - Credit Quality Indicators - MF (Details) - Multifamily - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	$ 8,098	$ 59,402
One fiscal year before	61,510	65,786
Two fiscal years before	65,226	76,984
Three fiscal years before	76,694	62,378
Four fiscal years before	62,093	51,270
Prior	163,417	116,402
Total mortgage loans	437,038	432,222
Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	8,098	57,976
One fiscal year before	59,264	64,165
Two fiscal years before	62,849	75,468
Three fiscal years before	74,920	59,507
Four fiscal years before	59,164	48,720
Prior	148,085	103,772
Total mortgage loans	412,380	409,608
Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	11
One fiscal year before	8	41
Two fiscal years before	99	128
Three fiscal years before	82	55
Four fiscal years before	24	54
Prior	293	306
Total mortgage loans	506	595
Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	1,415
One fiscal year before	2,238	1,580
Two fiscal years before	2,278	1,388
Three fiscal years before	1,692	2,816
Four fiscal years before	2,905	2,488
Prior	15,035	12,324
Total mortgage loans	24,148	22,011
Substandard | Senior Housing
Financing Receivable, Credit Quality Indicator [Line Items]
Total mortgage loans	8,900	9,200
Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
One fiscal year before	0	0
Two fiscal years before	0	0
Three fiscal years before	0	0
Four fiscal years before	0	8
Prior	4	0
Total mortgage loans	4	$ 8
Current-period write-offs
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0
One fiscal year before	3
Two fiscal years before	0
Three fiscal years before	1
Four fiscal years before	0
Prior	233
Total mortgage loans	$ 237