Pension Plans, Retirement Benefits and Savings Plans (details) - Miscellaneous Fair Value Disclosures	Dec. 31, 2017
Pension Plans [Member] | U.S. [Member] | Qualified Plan [Member] | Equity securities [Member] | Minimum [Member]
Defined benefit plan disclosure
Investment in class of securities (as a percentage)	55.00%
Pension Plans [Member] | U.S. [Member] | Qualified Plan [Member] | Equity securities [Member] | Maxiumum [Member]
Defined benefit plan disclosure
Investment in class of securities (as a percentage)	65.00%
Pension Plans [Member] | U.S. [Member] | Qualified Plan [Member] | Fixed income securities [Member] | Minimum [Member]
Defined benefit plan disclosure
Investment in class of securities (as a percentage)	20.00%
Pension Plans [Member] | U.S. [Member] | Qualified Plan [Member] | Fixed income securities [Member] | Maxiumum [Member]
Defined benefit plan disclosure
Investment in class of securities (as a percentage)	40.00%
Pension Plans [Member] | U.S. [Member] | Qualified Plan [Member] | Long-term growth [Member] | Minimum [Member]
Defined benefit plan disclosure
Investment in class of securities (as a percentage)	85.00%
Pension Plans [Member] | U.S. [Member] | Qualified Plan [Member] | Long-term growth [Member] | Maxiumum [Member]
Defined benefit plan disclosure
Investment in class of securities (as a percentage)	90.00%
Pension Plans [Member] | U.S. [Member] | Qualified Plan [Member] | Near-term benefit payments [Member] | Minimum [Member]
Defined benefit plan disclosure
Investment in class of securities (as a percentage)	10.00%
Pension Plans [Member] | U.S. [Member] | Qualified Plan [Member] | Near-term benefit payments [Member] | Maxiumum [Member]
Defined benefit plan disclosure
Investment in class of securities (as a percentage)	15.00%
Postretirement Benefit Plans [Member] | Fixed income securities [Member] | Minimum [Member]
Defined benefit plan disclosure
Investment in class of securities (as a percentage)	25.00%
Postretirement Benefit Plans [Member] | Fixed income securities [Member] | Maxiumum [Member]
Defined benefit plan disclosure
Investment in class of securities (as a percentage)	75.00%
Postretirement Benefit Plans [Member] | Long-term growth [Member] | Minimum [Member]
Defined benefit plan disclosure
Investment in class of securities (as a percentage)	35.00%
Postretirement Benefit Plans [Member] | Long-term growth [Member] | Maxiumum [Member]
Defined benefit plan disclosure
Investment in class of securities (as a percentage)	65.00%
Postretirement Benefit Plans [Member] | Near-term benefit payments [Member] | Minimum [Member]
Defined benefit plan disclosure
Investment in class of securities (as a percentage)	35.00%
Postretirement Benefit Plans [Member] | Near-term benefit payments [Member] | Maxiumum [Member]
Defined benefit plan disclosure
Investment in class of securities (as a percentage)	60.00%