Changes in Equity (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Changes in equity
Balance	$ 4,340,460	$ 4,102,289
Net income	24,691	32,836
Other comprehensive income	3,151	6,077
COMPREHENSIVE INCOME	27,842	38,913
Issuance of capital stock	2,592	2,574
Reissuance (purchase) of treasury stock - net	3,465	(6,271)
Other (primarily stock compensation)	3,342	14,825
Balance	4,377,701	4,152,330
Common Shareholders
Changes in equity
Balance	4,194,470	3,972,806
Net income	15,766	24,444
Other comprehensive income	3,151	6,077
COMPREHENSIVE INCOME	18,917	30,521
Issuance of capital stock	2,592	2,574
Reissuance (purchase) of treasury stock - net	3,465	(6,271)
Other (primarily stock compensation)	3,342	14,825
Balance	4,222,786	4,014,455
Noncontrolling Interests
Changes in equity
Balance	145,990	129,483
Net income	8,925	8,392
COMPREHENSIVE INCOME	8,925	8,392
Balance	$ 154,915	$ 137,875