Homebuilding Senior Notes and Other Debts Payable (Narrative) (Details) - USD ($)		6 Months Ended
	Jun. 30, 2019	May 31, 2019	Apr. 30, 2019	Mar. 31, 2019	Nov. 30, 2018
Senior Notes | 4.500% senior notes due 2019
Debt Instrument [Line Items]
Interest rate	4.50%	4.50%
Homebuilding
Debt Instrument [Line Items]
Guarantee by subsidiaries		$ 75,000,000
Homebuilding | Surety Bond
Debt Instrument [Line Items]
Outstanding performance and surety bonds		2,800,000,000
Uncompleted site improvements amount		$ 1,300,000,000
Uncompleted site improvements percent		46.00%
Homebuilding | Unsecured revolving credit facility
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 2,800,000,000
Accordion feature		400,000,000
Homebuilding | Unsecured revolving credit facility | Credit Facility Due in April 2023
Debt Instrument [Line Items]
Maximum borrowing capacity				$ 2,300,000,000
Homebuilding | Unsecured revolving credit facility | Credit Facility Due in April 2024
Debt Instrument [Line Items]
Maximum borrowing capacity			$ 2,400,000,000
Homebuilding | Unsecured revolving credit facility | Credit Facility Due in June 2020
Debt Instrument [Line Items]
Maximum borrowing capacity		50,000,000
Homebuilding | Letter of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity		315,000,000
Homebuilding | Performance Letters of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity		500,000,000
Letters of credit outstanding		663,000,000.0			$ 598,400,000
Homebuilding | Financial Letters of Credit
Debt Instrument [Line Items]
Letters of credit outstanding		158,500,000			165,400,000
Homebuilding | Senior Notes
Debt Instrument [Line Items]
Debt issuance cost		$ 26,900,000			$ 31,200,000
Homebuilding | Senior Notes | 4.500% senior notes due 2019
Debt Instrument [Line Items]
Interest rate		4.50%
Subsequent Event | Homebuilding | Senior Notes | 4.500% senior notes due 2019
Debt Instrument [Line Items]
Repayments of principal	$ 500,000,000
Redemption price	100.00%