Statements of Condensed Consolidated Equity (USD $) In Thousands, unless otherwise specified	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income	Noncontrolling Interests in Consolidated Subsidiaries
Balance at Dec. 31, 2012	$ 3,888,802	$ 1,308,771	$ 2,195,502	$ 99,547	$ 284,982
Balance (in shares) at Dec. 31, 2012		150,109
Increase (Decrease) in Stockholders' Equity
Net income	109,281		100,255		9,026
Other comprehensive loss	(77,965)			(77,965)
Dividends ($0.03 per share)	(4,516)		(4,516)
Stock-based compensation plans, net	16,465	16,323			142
Stock-based compensation plans, net (in shares)		326
Distributions to noncontrolling interests ($0.46 and $0.35 per common unit during the three months ended 2014 and 2013, respectively)	(5,031)				(5,031)
Balance at Mar. 31, 2013	3,927,036	1,325,094	2,291,241	21,582	289,119
Balance (in shares) at Mar. 31, 2013		150,435
Balance at Dec. 31, 2013	4,864,128	1,422,105	2,567,980	44,703	829,340
Balance (in shares) at Dec. 31, 2013		150,884
Increase (Decrease) in Stockholders' Equity
Net income	210,935		192,193		18,742
Other comprehensive loss	(21,719)			(21,719)
Dividends ($0.03 per share)	(4,542)		(4,542)
Stock-based compensation plans, net	(21,864)	(22,450)			586
Stock-based compensation plans, net (in shares)		867
Distributions to noncontrolling interests ($0.46 and $0.35 per common unit during the three months ended 2014 and 2013, respectively)	(12,432)				(12,432)
Balance at Mar. 31, 2014	$ 5,014,506	$ 1,399,655	$ 2,755,631	$ 22,984	$ 836,236
Balance (in shares) at Mar. 31, 2014		151,751