Long-Term Debt (Senior Notes) (Details) - USD ($)	Dec. 31, 2019	Mar. 11, 2019	Feb. 07, 2018	Jan. 25, 2018	Jan. 23, 2018	Apr. 07, 2016	Jul. 20, 2015	Apr. 01, 2015
Debt Instrument [Line Items]
Series A Preferred Unit, Redemption Amount				$ 313,000,000
Common Unit Repurchase, Unit Repurchased			17,286,859
Common Unit Repurchase, Cash Consideration			$ 540,000,000
Senior Notes [Member]
Debt Instrument [Line Items]
Debt face amount					$ 2,200,000,000
Senior Notes [Member] | Four Point Eight Seven Five Percentage Senior Notes Due Two Thousand Twenty Three [Member]
Debt Instrument [Line Items]
Debt face amount					$ 1,000,000,000.0
Stated interest rate	4.875%				4.875%
Senior Notes [Member] | Five Point Five Zero Zero Percentage Senior Notes Due Two Thousand Twenty Six [Member]
Debt Instrument [Line Items]
Debt face amount					$ 800,000,000
Stated interest rate	5.50%				5.50%
Senior Notes [Member] | Five Point Eight Seven Five Percentage Senior Notes Due Two Thousand Twenty Eight [Member]
Debt Instrument [Line Items]
Debt face amount					$ 400,000,000
Stated interest rate	5.875%				5.875%
Senior Notes [Member] | Six Point Two Five Zero Percentage Senior Notes Due Two Thousand Twenty One [Member]
Debt Instrument [Line Items]
Debt face amount						$ 800,000,000
Stated interest rate						6.25%
Senior Notes [Member] | Five Point Five Zero Zero Percentage Senior Notes Due Two Thousand Twenty [Member]
Debt Instrument [Line Items]
Debt face amount							$ 600,000,000
Stated interest rate							5.50%
Senior Notes [Member] | Six Point Three Seven Five Percentage Senior Notes Due Two Thousand Twenty Three [Member]
Debt Instrument [Line Items]
Debt face amount								$ 800,000,000
Stated interest rate								6.375%
Senior Notes [Member] | Six Percentage Senior Notes Due Two Thousand Twenty Seven [Member]
Debt Instrument [Line Items]
Debt face amount		$ 600,000,000
Stated interest rate	6.00%	6.00%