Pensions and Other Employee Benefits Plans (Pension Plans' Actual and Targeted Asset Allocations) (Details)		Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Actual Allocation		100.00%	100.00%
Target Allocation		100.00%
Liquid Return Seeking [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual Allocation		59.00%
Target Allocation		56.50%
Liquid Return Seeking [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation		45.00%
Liquid Return Seeking [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation		65.00%
Liquid Return Seeking - Multi Asset Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual Allocation	[1]	59.00%	60.00%
Fixed Income Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual Allocation		32.00%
Target Allocation		29.00%
Fixed Income Investments [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation		20.00%
Fixed Income Investments [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation		40.00%
Fixed Income Securities - Commingled Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual Allocation	[2]	32.00%	31.00%
Alternative Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual Allocation		9.00%	9.00%
Target Allocation		14.50%
Alternative Investments [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation		0.00%
Alternative Investments [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation		20.00%
Alternative investments - Equity Long/Short Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual Allocation	[3]	3.00%	3.00%
Alternative investments - Private Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual Allocation	[4]	0.00%	0.00%
Alternative investments - Distressed Opportunity Ltd. Partnership [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual Allocation	[5]	1.00%	2.00%
Alternative investments - Multi-Strategy Limited Partnerships [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual Allocation	[6]	5.00%	4.00%

[1] A single fund that invests in global equities, marketable real assets and fixed income securities. The fund has no limitation on redemptions.

[2] Investments in bonds representing many sectors of the broad bond market with both short-term and intermediate-term maturities. The fund has no limitation on redemptions.

[3] Investments primarily in long and short positions in equity securities of U.S. and non-U.S. companies. The fund generally has semi-annual tender offer redemption periods on June 30 and December 31 and is reported on a one month lag.

[4] Fund invests in portfolios of secondary interest in established venture capital, buyout, mezzanine and special situation funds on a global basis. Fund is valued on a quarterly lag with adjustment for subsequent cash activity. The fund terminates on June 26, 2019, subject to extension for up to three one-year periods. Earlier redemptions are not permitted.

[5] Investments mainly in discounted debt securities, bank loans, trade claims and other debt and equity securities of financially troubled companies. This partnership has semi-annual withdrawal rights on June 30 and December 31 with notice of 90 days and is reported on a one month lag.

[6] Investments in a partnership that has a multi-strategy investment program and does not rely on a single investment model. This partnership has quarterly redemption rights with notice of 65 days and is reported on a one month lag.