CONSOLIDATED STATEMENTS OF CASH FLOWS (unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Cash flows from operating activities:
Net income	$ 217,540	$ 201,688	$ 760,307	$ 718,332
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization			468,949	456,685
Debt prepayment, refinancing and redemption charges			86,957	33,402
Impairment charges			0	124,892
Stock-based compensation expense			67,217	47,811
Deferred income taxes			191,783	72,590
Equity investment income, net			3,026	5,131
Loss on sales of business interests, net			16,252	23,022
Other non-cash charges, net			(7,980)	24,291
Changes in operating assets and liabilities, net of effect of acquisitions and divestitures:
Accounts receivable			(12,405)	(182,684)
Inventories			(8,445)	9,519
Other receivables and other current assets			62,025	(51,319)
Other long-term assets			(1,853)	2,324
Accounts payable			445	(106,662)
Accrued compensation and benefits			(12,124)	(57,930)
Other current liabilities			123,833	140,046
Income taxes			(100,160)	57,279
Other long-term liabilities			(19,547)	(27,542)
Net cash provided by operating activities			1,494,230	1,391,825
Cash flows from investing activities:
Additions of property and equipment			(449,896)	(547,183)
Acquisitions			(112,597)	(77,348)
Proceeds from asset and business sales			83,339	3,863,619
Purchase of debt investments held-to-maturity			(147,829)	(98,322)
Purchase of other debt and equity investments			(3,388)	(5,160)
Proceeds from debt investments held-to-maturity			148,341	0
Proceeds from sale of other debt and equity investments			3,434	5,893
Purchase of equity method investments			(9,613)	(8,770)
Distributions from equity method investments			902	1,296
Net cash (used in) provided by investing activities			(487,307)	3,134,025
Cash flows from financing activities:
Borrowings			3,826,484	38,519,991
Payments on long-term debt			(3,927,411)	(40,485,415)
Deferred financing and debt redemption costs			(105,705)	(84,588)
Purchase of treasury stock			(1,025,878)	(1,837,022)
Distributions to noncontrolling interests			(179,098)	(157,170)
Stock award exercises and other share issuances, net			3,838	7,333
Contributions from noncontrolling interests			32,854	44,095
Purchases of noncontrolling interests			(6,782)	(10,988)
Net cash used in financing activities			(1,381,698)	(4,003,764)
Effect of exchange rate changes on cash, cash equivalents and restricted cash			(16,606)	(4,178)
Net (decrease) increase in cash, cash equivalents and restricted cash			(391,381)	517,908
Cash, cash equivalents and restricted cash of continuing operations at beginning of the year			1,208,718	415,420	$ 415,420
Cash, cash equivalents and restricted cash of continuing operations at end of the year	$ 817,337	$ 1,357,141	817,337	1,357,141	$ 1,208,718
Discontinued Operations
Cash flows from financing activities:
Net (decrease) increase in cash, cash equivalents and restricted cash			0	(423,813)
Continuing Operations
Cash flows from financing activities:
Net (decrease) increase in cash, cash equivalents and restricted cash			$ (391,381)	$ 941,721