|
Provision for Income Taxes - Expiration of Tax Loss Carryforwards (Detail) (USD $)
In Millions, unless otherwise specified |
Dec. 31, 2012
|
|---|---|
| Income Tax Disclosure [Line Items] | |
| Tax loss carryforwards | $ 2,515 |
|
2013 Tax loss carryforwards [Member]
|
|
| Income Tax Disclosure [Line Items] | |
| Tax loss carryforwards | 1 |
|
2014 Tax Loss Carryforwards [Member]
|
|
| Income Tax Disclosure [Line Items] | |
| Tax loss carryforwards | 5 |
|
2015 Tax Loss Carryforwards [Member]
|
|
| Income Tax Disclosure [Line Items] | |
| Tax loss carryforwards | 191 |
|
2016 Tax Loss Carryforwards [Member]
|
|
| Income Tax Disclosure [Line Items] | |
| Tax loss carryforwards | 748 |
|
2017 Tax Loss Carryforwards [Member]
|
|
| Income Tax Disclosure [Line Items] | |
| Tax loss carryforwards | 525 |
|
2018-2022 Tax Loss Carryforwards [Member]
|
|
| Income Tax Disclosure [Line Items] | |
| Tax loss carryforwards | 159 |
|
Later Tax Loss Carryforwards [Member]
|
|
| Income Tax Disclosure [Line Items] | |
| Tax loss carryforwards | 156 |
|
Unlimited Tax Credit Loss Carryforwards [Member]
|
|
| Income Tax Disclosure [Line Items] | |
| Tax loss carryforwards | $ 730 |