FAIR VALUE MEASUREMENTS (Details - Difference between fair values and the aggregate contractual principal amounts of mortgage and other loans receivable and long-term borrowings for which the fair value option was elected) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mortgage and other loans receivable, Fair Value	$ 5	$ 11
Mortgage and other loans receivable, Outstanding Principal Amount	37,345	33,537
Long-term debt, Fair Value	2,888	3,428
Long-term debt, Outstanding Principal Amount	31,640	30,912
Fair Value Option
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mortgage and other loans receivable, Fair Value	5	11
Mortgage and other loans receivable, Outstanding Principal Amount	5	8
Mortgage and other loans receivable, Difference	0	3
Long-term debt, Fair Value	2,888	3,428
Long-term debt, Outstanding Principal Amount	2,280	2,628
Long-term debt, Difference	$ 608	$ 800
Disclosure level, past due mortgage or other loans receivable for which the fair value option was elected, number of days past due threshold	0 days