Partnership Capital Subject to Mandatory Redemption - Roll Forward of Outstanding Partnership Loans (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Partners Capital Notes [Abstract]
Partnership loans outstanding at beginning of year	$ 341	$ 360	$ 332
Partnership loans issued during the year	222	163	164
Repayment of Partnership loans during the year	(242)	(182)
Partnership loans outstanding at end of year	$ 321	$ 341	$ 360