Pensions and Other Benefits - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified |
1 Months Ended | 3 Months Ended | 9 Months Ended | 12 Months Ended | 9 Months Ended | ||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Jan. 31, 2013
|
Sep. 30, 2013
|
Sep. 30, 2012
|
Sep. 30, 2013
|
Sep. 30, 2012
|
Sep. 30, 2013
USSC Pension Plan
|
Dec. 31, 2012
USSC Pension Plan
|
Sep. 30, 2013
Steelworkers Pension Trust
|
Sep. 30, 2013
Other Pension Plans, Defined Benefit
|
Sep. 30, 2013
Unfunded Other Postretirement Benefit Plans
|
Sep. 30, 2013
Defined Benefit Postretirement Health Coverage
|
|
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | |||||||||||
Defined Benefit Plan, Contributions by Employer | $ 63 | $ 56 | $ 18 | ||||||||
Cash contribution by employer to pension plans | 140 | 140 | 188 | 10 | |||||||
Cash contribution by employer to defined contribution plans | 11 | 10 | 33 | 31 | |||||||
Amount of voluntary pension funding authorized by the board of directors | 300 | ||||||||||
Long-term earnings rate assumption | 7.75% | ||||||||||
Estimated future contribution in 2014 | 140 | 140 | |||||||||
Estimated future contribution in 2015 | $ 140 | $ 140 |