Schedule I - Condensed Statements of Cash Flow (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 0	$ 0	$ 0
Adjustments to reconcile net income to net cash provided by operating activities:
Income before allocations to partners	1,605	1,285	1,092
Changes in assets and liabilities:
Other assets	(195)	(67)	(140)
Accounts payable and accrued expenses	227	32	161
Net cash provided by operating activities	2,395	25	13
CASH FLOWS FROM FINANCING ACTIVITIES:
Repayment of general partnership loans	(17)	0	0
Issuance of partnership interests	66	50	432
Redemption of partnership interests	(260)	(214)	(216)
Distributions from partnership capital	(1,153)	(864)	(783)
Net cash used in financing activities	(1,330)	(1,028)	(567)
Net increase (decrease) in cash, cash equivalents and restricted cash	831	(1,132)	(730)
CASH AND CASH EQUIVALENTS:
Beginning of year	6,875	8,007	8,737
End of year	7,706	6,875	8,007
NON-CASH ACTIVITIES:
Issuance of general partnership interests through partnership loans in current year	222	163	164
Repayment of partnership loans through distributions from partnership capital in current year	242	182
Declared distributions for retired partnership capital in current year but unpaid at year end	254	145	113
Parent Company [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	0	0	0
Adjustments to reconcile net income to net cash provided by operating activities:
Income before allocations to partners	1,605	1,285	1,092
Changes in assets and liabilities:
Investment in subsidiaries	(71)	(1)	(513)
Investment securities	(276)	(247)	5
Other assets	14	(6)	(16)
Accounts payable and accrued expenses	1	0	1
Net cash provided by operating activities	1,273	1,031	569
CASH FLOWS FROM FINANCING ACTIVITIES:
Repayment of general partnership loans	17	0	0
Issuance of partnership interests	66	50	432
Redemption of partnership interests	(260)	(214)	(216)
Distributions from partnership capital	(1,153)	(864)	(783)
Net cash used in financing activities	(1,330)	(1,028)	(567)
Net increase (decrease) in cash, cash equivalents and restricted cash	(57)	3	2
CASH AND CASH EQUIVALENTS:
Beginning of year	323	320	318
End of year	266	323	320
NON-CASH ACTIVITIES:
Issuance of general partnership interests through partnership loans in current year	222	163	164
Repayment of partnership loans through distributions from partnership capital in current year	225	182	136
Declaration of distributions from subsidiary in current year but received after year end	434	474	428
Declared distributions for retired partnership capital in current year but unpaid at year end	$ 254	$ 145	$ 109