SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION CONDENSED CONSOLIDATING FINANCIAL STATEMENTS, Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating activities
Cash provided by operating activities	$ 2,186,719	$ 1,315,412	$ 1,353,220
Investing activities
Capital expenditures	(2,141,475)	(512,393)	(624,634)
Contributions to unconsolidated affiliates	(1,748)	(87,861)	(68,275)
Cash provided by (used in) investing activities	(2,114,888)	(567,633)	(615,445)
Financing activities
Dividends paid	(1,335,058)	(829,414)	(517,601)
Distributions to noncontrolling interests	(3,500)	(276,260)	(549,419)
Borrowing (repayment) of short-term borrowings, net	(614,673)	(495,604)	563,937
Issuance of long-term debt, net of discounts	1,795,773	1,190,496	1,000,000
Debt financing costs	(13,441)	(11,425)	(2,770)
Repayment of long-term debt	(932,650)	(994,776)	(1,108,040)
Issuance of common stock	1,203,981	471,358	21,971
Acquisition of noncontrolling interests	(195,000)	0	0
Other, net	(2,481)	(13,836)	5,403
Cash used in financing activities	(97,049)	(959,461)	(586,519)
Change in cash and cash equivalents	(25,218)	(211,682)	151,256
Cash and cash equivalents at beginning of period	37,193	248,875	97,619
Cash and cash equivalents at end of period	11,975	37,193	248,875
Reportable Legal Entities | Parent Issuer & Guarantor
Operating activities
Cash provided by operating activities	1,325,100	947,400	717,000
Investing activities
Capital expenditures	(18,800)	0	(200)
Contributions to unconsolidated affiliates		0
Other investing activities	0	0	0
Cash provided by (used in) investing activities	(18,800)	0	(200)
Financing activities
Dividends paid	(1,335,100)	(829,400)	(517,600)
Distributions to noncontrolling interests	0	0	0
Intercompany borrowings (advances), net	(2,154,400)	(2,500,700)	(63,100)
Borrowing (repayment) of short-term borrowings, net	(614,700)	614,700	0
Issuance of long-term debt, net of discounts	1,795,800	1,190,500	0
Debt financing costs			0
Repayment of long-term debt	0	(87,100)	(300)
Issuance of common stock	1,204,000	471,400	22,000
Acquisition of noncontrolling interests	(195,000)
Other, net	(32,100)	(18,100)	(1,700)
Cash used in financing activities	(1,331,500)	(1,158,700)	(560,700)
Change in cash and cash equivalents	(25,200)	(211,300)	156,100
Change in cash and cash equivalents included in discontinued operations			(100)
Change in cash and cash equivalents included in continuing operations			156,000
Cash and cash equivalents at beginning of period	37,200	248,500	92,500
Cash and cash equivalents at end of period	12,000	37,200	248,500
Reportable Legal Entities | Subsidiary Issuer & Guarantor
Operating activities
Cash provided by operating activities	1,344,700	1,348,300	1,334,500
Investing activities
Capital expenditures	0	0	0
Contributions to unconsolidated affiliates		0
Other investing activities	0	0	0
Cash provided by (used in) investing activities	0	0	0
Financing activities
Dividends paid	(1,332,000)	(1,332,000)	(1,332,000)
Distributions to noncontrolling interests	0	0	0
Intercompany borrowings (advances), net	912,300	2,001,200	(470,800)
Borrowing (repayment) of short-term borrowings, net	0	(1,110,300)	563,900
Issuance of long-term debt, net of discounts	0	0	1,000,000
Debt financing costs			(2,800)
Repayment of long-term debt	(925,000)	(900,000)	(1,100,000)
Issuance of common stock	0	0	0
Acquisition of noncontrolling interests	0
Other, net	0	(7,200)	7,200
Cash used in financing activities	(1,344,700)	(1,348,300)	(1,334,500)
Change in cash and cash equivalents	0	0	0
Change in cash and cash equivalents included in discontinued operations			0
Change in cash and cash equivalents included in continuing operations			0
Cash and cash equivalents at beginning of period	0	0	0
Cash and cash equivalents at end of period	0	0	0
Reportable Legal Entities | Guarantor Subsidiary
Operating activities
Cash provided by operating activities	67,900	59,000	70,000
Investing activities
Capital expenditures	0	0	0
Contributions to unconsolidated affiliates		(83,000)
Other investing activities	15,300	14,800	34,900
Cash provided by (used in) investing activities	15,300	(68,200)	34,900
Financing activities
Dividends paid	(1,332,000)	(1,332,000)	(1,332,000)
Distributions to noncontrolling interests	0	0	0
Intercompany borrowings (advances), net	1,248,800	1,340,800	1,222,400
Borrowing (repayment) of short-term borrowings, net	0	0	0
Issuance of long-term debt, net of discounts	0	0	0
Debt financing costs			0
Repayment of long-term debt	0	0	0
Issuance of common stock	0	0	0
Acquisition of noncontrolling interests	0
Other, net	0	0	0
Cash used in financing activities	(83,200)	8,800	(109,600)
Change in cash and cash equivalents	0	(400)	(4,700)
Change in cash and cash equivalents included in discontinued operations			0
Change in cash and cash equivalents included in continuing operations			(4,700)
Cash and cash equivalents at beginning of period	0	400	5,100
Cash and cash equivalents at end of period	0	0	400
Reportable Legal Entities | Combined Non-Guarantor Subsidiaries
Operating activities
Cash provided by operating activities	2,113,000	1,353,700	1,353,900
Investing activities
Capital expenditures	(2,122,700)	(512,400)	(624,400)
Contributions to unconsolidated affiliates		(4,900)
Other investing activities	11,300	17,900	(25,700)
Cash provided by (used in) investing activities	(2,111,400)	(499,400)	(650,100)
Financing activities
Dividends paid	0	0	0
Distributions to noncontrolling interests	(3,500)	(5,300)	(7,500)
Intercompany borrowings (advances), net	(6,700)	(841,300)	(688,500)
Borrowing (repayment) of short-term borrowings, net	0	0	0
Issuance of long-term debt, net of discounts	0	0	0
Debt financing costs			0
Repayment of long-term debt	(7,700)	(7,700)	(7,700)
Issuance of common stock	0	0	0
Acquisition of noncontrolling interests	0
Other, net	16,300	0	(100)
Cash used in financing activities	(1,600)	(854,300)	(703,800)
Change in cash and cash equivalents	0	0	0
Change in cash and cash equivalents included in discontinued operations			0
Change in cash and cash equivalents included in continuing operations			0
Cash and cash equivalents at beginning of period	0	0	0
Cash and cash equivalents at end of period	0	0	0
Reportable Legal Entities | Total
Operating activities
Cash provided by operating activities	2,186,700	1,315,400	1,353,300
Investing activities
Capital expenditures	(2,141,500)	(512,400)	(624,600)
Contributions to unconsolidated affiliates		(87,900)
Other investing activities	26,600	32,700	9,200
Cash provided by (used in) investing activities	(2,114,900)	(567,600)	(615,400)
Financing activities
Dividends paid	(1,335,100)	(829,400)	(517,600)
Distributions to noncontrolling interests	(3,500)	(276,300)	(549,400)
Intercompany borrowings (advances), net	0	0	0
Borrowing (repayment) of short-term borrowings, net	(614,700)	(495,600)	563,900
Issuance of long-term debt, net of discounts	1,795,800	1,190,500	1,000,000
Debt financing costs			(2,800)
Repayment of long-term debt	(932,700)	(994,800)	(1,108,000)
Issuance of common stock	1,204,000	471,400	22,000
Acquisition of noncontrolling interests	(195,000)
Other, net	(15,800)	(25,300)	5,400
Cash used in financing activities	(97,000)	(959,500)	(586,500)
Change in cash and cash equivalents	(25,200)	(211,700)	151,400
Change in cash and cash equivalents included in discontinued operations			(100)
Change in cash and cash equivalents included in continuing operations			151,300
Cash and cash equivalents at beginning of period	37,200	248,900	97,600
Cash and cash equivalents at end of period	12,000	37,200	248,900
Consolidating Entries
Operating activities
Cash provided by operating activities	(2,664,000)	(2,393,000)	(2,122,100)
Investing activities
Capital expenditures	0	0	0
Contributions to unconsolidated affiliates		0
Other investing activities	0	0	0
Cash provided by (used in) investing activities	0	0	0
Financing activities
Dividends paid	2,664,000	2,664,000	2,664,000
Distributions to noncontrolling interests	0	(271,000)	(541,900)
Intercompany borrowings (advances), net	0	0	0
Borrowing (repayment) of short-term borrowings, net	0	0	0
Issuance of long-term debt, net of discounts	0	0	0
Debt financing costs			0
Repayment of long-term debt	0	0	0
Issuance of common stock	0	0	0
Acquisition of noncontrolling interests	0
Other, net	0	0	0
Cash used in financing activities	2,664,000	2,393,000	2,122,100
Change in cash and cash equivalents	0	0	0
Change in cash and cash equivalents included in discontinued operations			0
Change in cash and cash equivalents included in continuing operations			0
Cash and cash equivalents at beginning of period	0	0	0
Cash and cash equivalents at end of period	$ 0	$ 0	$ 0