Marketable Securities and Derivative Instruments: Marketable Securities (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Available-for-sale Securities, Gross Realized Gain (Loss), Disclosures [Abstract]
Available For Sale Securities Gross Realized Gains Losses Sale Proceeds	$ 58,718,000	$ 69,559,000	$ 281,486,000
Available-for-sale Securities, Gross Realized Gain (Loss)	3,582,000	5,020,000	22,604,000
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Debt Securities	0	57,525,000
Marketable securities	398,188,000	741,321,000
Available-for-sale Debt Securities, Amortized Cost Basis	0	53,941,000
Non-cash impairment loss on J.C. Penney owned shares	224,937,000	0	0
JC Penney [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Equity Securities	366,291,000	653,228,000
Available-for-sale Equity Securities, Amortized Cost Basis	366,291,000	591,069,000
Available-for-sale Securities, Gross Unrealized Gain (Loss)	0	62,159,000
Non-cash impairment loss on J.C. Penney owned shares	224,937,000
Other Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Equity Securities	31,897,000	30,568,000
Available-for-sale Equity Securities, Amortized Cost Basis	12,021,000	14,585,000
Available-for-sale Securities, Gross Unrealized Gain (Loss)	19,876,000	15,983,000
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross Unrealized Gain (Loss)	$ 0	$ 3,584,000