Retirement Plans (Details) (USD $) In Millions, unless otherwise specified | 3 Months Ended | 12 Months Ended | 3 Months Ended | 9 Months Ended | 3 Months Ended | 9 Months Ended | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Jun. 30, 2011 | Dec. 31, 2010 | Sep. 30, 2011
Pension Benefits [Member] | Sep. 30, 2010
Pension Benefits [Member] | Sep. 30, 2011
Pension Benefits [Member] | Sep. 30, 2010
Pension Benefits [Member] | Sep. 30, 2010
Other Postretirement Benefits [Member] | Sep. 30, 2011
Other Postretirement Benefits [Member] | Sep. 30, 2010
Other Postretirement Benefits [Member] | Dec. 31, 2010
Previous Estimate [Member] | Sep. 30, 2011
Current Estimate [Member] | |
| Service cost | $ 10 | $ 9 | $ 28 | $ 25 | $ 1 | ||||||
| Interest cost | 15 | 15 | 45 | 43 | 1 | 1 | 3 | ||||
| Expected return on plan assets | (11) | (10) | (32) | (28) | |||||||
| Amortization of prior service cost | 1 | 3 | 2 | 1 | (1) | 1 | |||||
| Net actuarial loss | 8 | 7 | 24 | 21 | |||||||
| Net periodic benefit cost | 23 | 21 | 68 | 63 | 2 | 1 | 4 | ||||
| Estimated qualified pension plan contribution | $ 84 | $ 446 | |||||||||
| Allocation percentage for equity securities | 20.00% | 47.50% | |||||||||
| Allocation percentage for fixed income | 70.00% | 40.00% | |||||||||
| Allocation percentage for other investment types | 10.00% | 12.50% | |||||||||
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- Definition The amount of gains or losses recognized in net periodic benefit cost. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The amount of the prior service cost or credit recognized in net periodic benefit cost relating to benefit changes attributable to plan participants' prior service pursuant to a plan amendment or a plan initiation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The employer's best estimate, as soon as it can be reasonably determined, of contributions expected to be paid to the plan during the next fiscal year beginning after the date of the latest statement of financial position. Estimated contributions may be presented in the aggregate combining (1) contributions required by funding regulations or laws, (2) discretionary contributions, and (3) noncash contributions. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition An amount calculated as a basis for determining the extent of delayed recognition of the effects of changes in the fair value of assets. The expected return on plan assets is determined based on the expected long-term rate of return on plan assets and the market-related value of plan assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The increase in a defined benefit pension plan's projected benefit obligation or a defined benefit postretirement plan's accumulated postretirement benefit obligation due to the passage of time. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The total amount of net periodic benefit cost for defined benefit plans for the period. Periodic benefit costs include the following components: service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) due to settlements or curtailments. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The actuarial present value of benefits attributed by the pension benefit formula to services rendered by employees during the period. The portion of the expected postretirement benefit obligation attributed to employee service during the period. The service cost component is a portion of the benefit obligation and is unaffected by the funded status of the plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Target allocation percentage of investments in debt securities to total plan assets presented on a weighted-average basis as of the measurement date of the latest statement of financial position. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Target allocation percentage of investments in equity securities to total plan assets presented on a weighted-average basis as of the measurement date of the latest statement of financial position.
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- Definition Target allocation percentage in other than debt securities, equity securities, and real estate to total plan assets presented on a weighted-average basis as of the measurement date of the latest statement of financial position.
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