Schedule I - Condensed Financial Information of Parent Company (Balance Sheets) (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
CURRENT ASSETS
Cash and cash equivalents	$ 23	$ 25	$ 109	$ 21
Prepayments of income taxes	40	59
Total Current Assets	1,398	1,267
Investments and Other Assets
Goodwill	1,407	1,407
Other	163	163
TOTAL ASSETS	14,848	15,794
CURRENT LIABILITIES
Short-term debt	565	965
Total Current Liabilities	2,313	2,543
DEFERRED CREDITS
Liabilities and accrued interest related to uncertain tax positions	28	15
Long-term debt	4,053	3,648
COMMITMENTS AND CONTINGENCIES
EQUITY
Common stock	3	2
Premium on stock and other capital contributions	3,751	3,383
Accumulated other comprehensive loss	(34)	(48)
Retained earnings	595	1,077	1,040	1,027
TOTAL LIABILITIES AND EQUITY	14,848	15,794
Parent Company [Member]
CURRENT ASSETS
Cash and cash equivalents		262	257	131
Prepayments of income taxes	151	12
Accounts receivable and other	28	7
Total Current Assets	179	281
Investments and Other Assets
Goodwill	1,398	1,398
Investment in consolidated companies	3,935	2,633
Net assets associated with investment in consolidated companies held for disposition		1,232
Other	37	55
Total Investments and Other Assets	5,370	5,318	5,198	4,927
TOTAL ASSETS	5,549	5,599
CURRENT LIABILITIES
Short-term debt	24	464
Interest and taxes accrued	10	11
Accounts payable due to associated companies	1	2
Total Current Liabilities	35	477
DEFERRED CREDITS
Notes payable due to subsidiary companies	491
Liabilities and accrued interest related to uncertain tax positions	3	3
Total Deferred Credits	494	3
Long-term debt	705	705
COMMITMENTS AND CONTINGENCIES
EQUITY
Common stock	3	2
Premium on stock and other capital contributions	3,751	3,383
Accumulated other comprehensive loss	(34)	(48)
Retained earnings	595	1,077	1,040	1,027
Total equity	4,315	4,414
TOTAL LIABILITIES AND EQUITY	$ 5,549	$ 5,599