Retirement Benefits and Trusteed Assets (Pension Plan - Fair Value Measurement using Level 3 Inputs) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plans Fair Value Measurements Using Significant Unobservale Inputs [Line Items]
The amount of total gains (losses) included in net income attributed to the change in unrealized gains or losses related to assets still held at the end of the period	$ 2	$ 1
Pension Plans, Defined Benefit [Member]
Defined Benefit Plans Fair Value Measurements Using Significant Unobservale Inputs [Line Items]
Beginning Balance	363	321
Realized gains (losses)	12	9
Unrealized gains (losses)	19	5
Purchases	33	199
Sales	(20)	(171)
Ending Balance	407	363
The amount of total gains (losses) included in net income attributed to the change in unrealized gains or losses related to assets still held at the end of the period	29	15
Pension Plans, Defined Benefit [Member] | Hedge Funds and Similar Investments [Member]
Defined Benefit Plans Fair Value Measurements Using Significant Unobservale Inputs [Line Items]
Beginning Balance	238	205
Realized gains (losses)	0	13
Unrealized gains (losses)	29	(3)
Purchases	18	176
Sales	0	(153)
Ending Balance	285	238
The amount of total gains (losses) included in net income attributed to the change in unrealized gains or losses related to assets still held at the end of the period	27	11
Pension Plans, Defined Benefit [Member] | Private Equity and Other [Member]
Defined Benefit Plans Fair Value Measurements Using Significant Unobservale Inputs [Line Items]
Beginning Balance	125	116
Realized gains (losses)	12	(4)
Unrealized gains (losses)	(10)	8
Purchases	15	23
Sales	(20)	(18)
Ending Balance	122	125
The amount of total gains (losses) included in net income attributed to the change in unrealized gains or losses related to assets still held at the end of the period	$ 2	$ 4