SCHEDULE I, CONDENSED FINANCIAL INFORMATION OF PARENT, BALANCE SHEETS (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
ASSETS
Cash and cash equivalents	$ 570,000,000	$ 904,000,000	$ 475,000,000	$ 252,000,000
Due from affiliates	38,000,000us-gaap_DueFromAffiliateCurrent	4,000,000us-gaap_DueFromAffiliateCurrent
Deferred income taxes	305,000,000us-gaap_DeferredTaxAssetsNetCurrent	301,000,000us-gaap_DeferredTaxAssetsNetCurrent
Other current assets	293,000,000us-gaap_OtherAssetsCurrent	208,000,000us-gaap_OtherAssetsCurrent
Total current assets	4,184,000,000us-gaap_AssetsCurrent	3,997,000,000us-gaap_AssetsCurrent
Investments in subsidiaries	2,848,000,000	1,575,000,000
Due from affiliaties	188,000,000us-gaap_DueFromAffiliateNoncurrent	14,000,000us-gaap_DueFromAffiliateNoncurrent
Other assets	561,000,000us-gaap_OtherAssetsNoncurrent	635,000,000us-gaap_OtherAssetsNoncurrent
Total assets	39,732,000,000us-gaap_Assets	37,244,000,000us-gaap_Assets	36,499,000,000us-gaap_Assets
LIABILITIES AND EQUITY
Current portion of long-term debt	469,000,000	1,147,000,000
Due to affiliaties	2,000,000us-gaap_DueToAffiliateCurrent	0us-gaap_DueToAffiliateCurrent
Other current liabilities	649,000,000us-gaap_OtherLiabilitiesCurrent	515,000,000us-gaap_OtherLiabilitiesCurrent
Long-term debt	12,167,000,000	11,253,000,000
Total current liabilities	5,069,000,000us-gaap_LiabilitiesCurrent	4,369,000,000us-gaap_LiabilitiesCurrent
Other long-term liabilities	1,104,000,000us-gaap_OtherLiabilitiesNoncurrent	1,169,000,000us-gaap_OtherLiabilitiesNoncurrent
Total shareholders' equity	11,326,000,000us-gaap_StockholdersEquity	11,008,000,000us-gaap_StockholdersEquity
Total liabilities and equity	39,732,000,000	37,244,000,000
Parent Company [Member]
ASSETS
Cash and cash equivalents	3,000,000	6,000,000	18,000,000	11,000,000
Due from affiliates	101,000,000	132,000,000
Deferred income taxes	398,000,000	170,000,000
Other current assets	15,000,000	16,000,000
Total current assets	517,000,000	324,000,000
Investments in subsidiaries	14,557,000,000	13,866,000,000
Due from affiliaties	174,000,000	802,000,000
Deferred Tax Assets	1,544,000,000	1,466,000,000
Other assets	631,000,000	555,000,000
Total assets	17,423,000,000	17,013,000,000
LIABILITIES AND EQUITY
Current portion of long-term debt	0	800,000,000
Due to affiliaties	338,000,000	273,000,000
Income taxes payable	93,000,000	64,000,000
Other current liabilities	271,000,000	276,000,000
Long-term debt	4,666,000,000	4,117,000,000
Total current liabilities	702,000,000	1,413,000,000
Due to affiliates	230,000,000	0
Other long-term liabilities	499,000,000	475,000,000
Total shareholders' equity	11,326,000,000	11,008,000,000
Total liabilities and equity	$ 17,423,000,000	$ 17,013,000,000

Carrying amount as of the balance sheet date of the unpaid sum of the known and estimated amounts payable to satisfy all currently due domestic and foreign income tax obligations.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 20

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.20)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 15

-Article 9

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 15

-Subparagraph b(1)

-Article 7