Significant Accounting Policies - Effects of Revision on PHI's Consolidated Balance Sheets (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Deferred income tax liabilities, net		$ 3,208	$ 2,895
Total deferred credits	3,883	4,851	4,581
Retained earnings	595	1,077	1,040	1,027
Total equity	4,315	4,414	4,304	4,198
As Filed [Member]
Deferred income tax liabilities, net		3,176	2,863
Total deferred credits		4,819	4,549
Retained earnings		1,109	1,072	1,059
Total equity		4,446	4,336	4,230
Adjustment [Member]
Deferred income tax liabilities, net		32	32
Total deferred credits		32	32
Retained earnings		(32)	(32)	(32)
Total equity		$ (32)	$ (32)	$ (32)