Loans and finance receivables - Summary of performing and non-performing home loans before discounts and allowances by year of loan origination (Detail) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and financing receivables by origination year, Total	$ 25,573	$ 24,664
Manufactured Housing Loan Balances [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and financing receivables by origination year, 2023	4,478
Loans and financing receivables by origination year, 2022	4,472
Loans and financing receivables by origination year, 2021	3,404
Loans and financing receivables by origination year, 2020	2,641
Loans and financing receivables by origination year, 2019	1,869
Loans and financing receivables by origination year, Prior	7,723
Loans and financing receivables by origination year, Total	24,587
Performing [Member] | Manufactured Housing Loan Balances [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and financing receivables by origination year, 2023	4,474
Loans and financing receivables by origination year, 2022	4,466
Loans and financing receivables by origination year, 2021	3,394
Loans and financing receivables by origination year, 2020	2,633
Loans and financing receivables by origination year, 2019	1,861
Loans and financing receivables by origination year, Prior	7,681
Loans and financing receivables by origination year, Total	24,509
Non-Performing [Member] | Manufactured Housing Loan Balances [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and financing receivables by origination year, 2023	4
Loans and financing receivables by origination year, 2022	6
Loans and financing receivables by origination year, 2021	10
Loans and financing receivables by origination year, 2020	8
Loans and financing receivables by origination year, 2019	8
Loans and financing receivables by origination year, Prior	42
Loans and financing receivables by origination year, Total	$ 78