Changes in Equity (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Changes in equity
Balance at beginning of period	$ 3,930,586	$ 3,775,226
NET INCOME (LOSS)	(481)	(9,674)
OCI (loss)	(15,614)	10,446
COMPREHENSIVE INCOME (LOSS)	(16,095)	772
Issuance of capital stock	2,700	2,689
Purchase of treasury stock, net of reissuances	(1,754)	(3,530)
Other (primarily stock compensation)	3,350	10,723
Dividends on common stock	(57,358)	(57,109)
Balance at end of period	3,861,429	3,728,771
Common Shareholders
Changes in equity
Balance at beginning of period	3,821,850	3,683,327
NET INCOME (LOSS)	(8,257)	(15,135)
OCI (loss)	(15,614)	10,446
COMPREHENSIVE INCOME (LOSS)	(23,871)	(4,689)
Issuance of capital stock	2,700	2,689
Purchase of treasury stock, net of reissuances	(1,754)	(3,530)
Other (primarily stock compensation)	3,350	10,723
Dividends on common stock	(57,358)	(57,109)
Balance at end of period	3,744,917	3,631,411
Noncontrolling Interests
Changes in equity
Balance at beginning of period	108,736	91,899
NET INCOME (LOSS)	7,776	5,461
COMPREHENSIVE INCOME (LOSS)	7,776	5,461
Balance at end of period	$ 116,512	$ 97,360