Consolidated Statements Of Changes In Equity - USD ($) shares in Thousands, $ in Thousands	Total	Total Equity [Member]	Total Shareholders' Equity [Member]	Common Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income [Member]	Noncontrolling Interests [Member]	Redeemable Noncontrolling Interests [Member]
Balance at Dec. 31, 2015		$ 7,840,609	$ 7,834,150	$ 3,342,357	$ 3,137,285	$ 1,354,508	$ 6,459
Balance, shares at Dec. 31, 2015				13,959
Balance, redeemable noncontrolling interests at Dec. 31, 2015								$ 62,958
Net income (loss)	$ 244,319	239,957	239,167		239,167	0	790	4,362
Other comprehensive income	367,788	367,769	367,769		0	367,769	0	19
Comprehensive Income	612,107	607,726	606,936				790	4,381
Issuance of common stock		4,101	4,101	$ 4,101	0	0	0	0
Issuance of common stock, shares				48
Repurchase of common stock		(15,206)	(15,206)	$ 0	(15,206)	0	0	0
Repurchase of common stock, shares				(16)
Restricted stock units expensed		13,473	13,473	$ 13,473	0	0	0	0
Restricted stock units expensed, shares				0
Adjustment of redeemable noncontrolling interests		(5,981)	(5,981)	$ 0	(5,981)	0	0	5,981
Adjustment of redeemable noncontrolling interests, shares				0
Purchase of noncontrolling interest		899	899	$ 899	0	0	0	(3,977)
Purchase of noncontrolling interest, shares				0
Other		(48)	(3)	$ 0	(3)	0	(45)	(3,142)
Other, shares				0
Balance at Jun. 30, 2016		8,445,573	8,438,369	$ 3,360,830	3,355,262	1,722,277	7,204
Balance, shares at Jun. 30, 2016				13,991
Balance, redeemable noncontrolling interests at Jun. 30, 2016								66,201
Balance at Dec. 31, 2016	8,467,411	8,467,411	8,460,927	$ 3,368,666	3,526,395	1,565,866	6,484
Balance, shares at Dec. 31, 2016				13,955
Balance, redeemable noncontrolling interests at Dec. 31, 2016	73,678							73,678
Net income (loss)	222,467	219,222	219,529		219,529	0	(307)	3,245
Other comprehensive income	346,083	346,067	346,067		0	346,067	0	16
Comprehensive Income	568,550	565,289	565,596				(307)	3,261
Issuance of common stock		359	359	$ 359	0	0	0	0
Issuance of common stock, shares				24
Repurchase of common stock		(59,194)	(59,194)	$ 0	(59,194)	0	0	0
Repurchase of common stock, shares				(61)
Restricted stock units expensed		10,568	10,568	$ 10,568	0	0	0	0
Restricted stock units expensed, shares				0
Adjustment of redeemable noncontrolling interests		(20,284)	(20,284)	$ 0	(20,284)	0	0	20,284
Adjustment of redeemable noncontrolling interests, shares				0
Purchase of noncontrolling interest		(11,019)	(2,910)	$ (2,910)	0	0	(8,109)	(6,179)
Purchase of noncontrolling interest, shares				0
Other		(614)	(653)	$ (453)	(200)	0	39	(4,353)
Other, shares				0
Balance at Jun. 30, 2017	8,952,516	$ 8,952,516	$ 8,954,409	$ 3,376,230	$ 3,666,246	$ 1,911,933	$ (1,893)
Balance, shares at Jun. 30, 2017				13,918
Balance, redeemable noncontrolling interests at Jun. 30, 2017	$ 86,691							$ 86,691