|
Debt (Consolidated Debt) (Details) (USD $)
|
Jun. 30, 2014
|
Dec. 31, 2013
|
||||||
|---|---|---|---|---|---|---|---|---|
| Debt Instrument [Line Items] | ||||||||
| Total debt | $ 2,910,496,000 | $ 2,685,287,000 | ||||||
| Weighted-Average Interest Rate | 5.10% | [1] | ||||||
| Debt Instrument, Face Amount | 2,900,000,000.0 | 2,700,000,000.0 | ||||||
|
Commercial Paper [Member]
|
||||||||
| Debt Instrument [Line Items] | ||||||||
| Total debt | 220,977,000 | [2] | 0 | [2] | ||||
| Weighted-Average Interest Rate | 0.30% | [1],[2] | ||||||
|
Revolving Credit Facility [Member]
|
||||||||
| Debt Instrument [Line Items] | ||||||||
| Total debt | 0 | [2] | 0 | [2] | ||||
| Weighted-Average Interest Rate | 1.30% | [1],[2] | ||||||
|
Senior Notes [Member] | 6.45% Notes Due 2014 [Member]
|
||||||||
| Debt Instrument [Line Items] | ||||||||
| Total debt | 0 | [2] | 249,971,000 | [2] | ||||
| Weighted-Average Interest Rate | 6.30% | [1],[2] | ||||||
| Debt Instrument, Face Amount | 250,000,000.0 | |||||||
| Debt Instrument, Interest Rate, Stated Percentage | 6.45% | |||||||
|
Senior Notes [Member] | 5.65% Notes Due 2016 [Member]
|
||||||||
| Debt Instrument [Line Items] | ||||||||
| Total debt | 250,970,000 | 251,183,000 | ||||||
| Weighted-Average Interest Rate | 5.70% | [1] | ||||||
| Debt Instrument, Face Amount | 250,000,000.0 | |||||||
| Debt Instrument, Interest Rate, Stated Percentage | 5.65% | |||||||
|
Senior Notes [Member] | 6.40% Notes Due 2018 [Member]
|
||||||||
| Debt Instrument [Line Items] | ||||||||
| Total debt | 258,313,000 | 259,346,000 | ||||||
| Weighted-Average Interest Rate | 5.40% | [1] | ||||||
| Debt Instrument, Face Amount | 250,000,000.0 | |||||||
| Debt Instrument, Interest Rate, Stated Percentage | 6.40% | |||||||
|
Senior Notes [Member] | 6.55% Notes Due 2019 [Member]
|
||||||||
| Debt Instrument [Line Items] | ||||||||
| Total debt | 569,704,000 | 571,515,000 | ||||||
| Weighted-Average Interest Rate | 5.70% | [1] | ||||||
| Debt Instrument, Face Amount | 550,000,000.0 | |||||||
| Debt Instrument, Interest Rate, Stated Percentage | 6.55% | |||||||
|
Senior Notes [Member] | 4.25% Notes Due 2021 [Member]
|
||||||||
| Debt Instrument [Line Items] | ||||||||
| Total debt | 556,763,000 | 557,213,000 | ||||||
| Weighted-Average Interest Rate | 4.00% | [1] | ||||||
| Debt Instrument, Face Amount | 550,000,000.0 | |||||||
| Debt Instrument, Interest Rate, Stated Percentage | 4.25% | |||||||
|
Senior Notes [Member] | 6.40% Notes Due 2037 [Member]
|
||||||||
| Debt Instrument [Line Items] | ||||||||
| Total debt | 249,007,000 | 248,998,000 | ||||||
| Weighted-Average Interest Rate | 6.40% | [1] | ||||||
| Debt Instrument, Face Amount | 250,000,000.0 | |||||||
| Debt Instrument, Interest Rate, Stated Percentage | 6.40% | |||||||
|
Senior Notes [Member] | 4.20% Notes Due 2042 [Member]
|
||||||||
| Debt Instrument [Line Items] | ||||||||
| Total debt | 248,391,000 | 248,377,000 | ||||||
| Weighted-Average Interest Rate | 4.20% | [1] | ||||||
| Debt Instrument, Face Amount | 250,000,000.0 | |||||||
| Debt Instrument, Interest Rate, Stated Percentage | 4.20% | |||||||
|
Senior Notes [Member] | 5.15% Notes Due 2043 [Member]
|
||||||||
| Debt Instrument [Line Items] | ||||||||
| Total debt | 556,371,000 | 298,684,000 | ||||||
| Weighted-Average Interest Rate | 5.10% | [1] | ||||||
| Debt Instrument, Face Amount | $ 550,000,000.0 | |||||||
| Debt Instrument, Interest Rate, Stated Percentage | 5.15% | |||||||
|
||||||||