Debt and Financing Cost - Non-Recurring Fair Value Measurement (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Total Debt, Carrying Amount	$ 9,673	$ 9,725
Total Debt, Fair Value	10,762	10,300
Uncommitted Credit Lines [Member]
Debt Instrument [Line Items]
Uncommitted credit lines, Carrying Amount		53
Total Debt, Fair Value		53
Notes and Debentures [Member]
Debt Instrument [Line Items]
Notes and debentures, Carrying Amount	9,673	9,672
Total Debt, Fair Value	$ 10,762	$ 10,247