Retirement Benefits (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended	3 Months Ended		12 Months Ended	3 Months Ended	0 Months Ended
	Mar. 31, 2013 AA [Member]	Dec. 31, 2013 AA [Member]	Mar. 31, 2014 Pension Plans [Member]	Mar. 31, 2013 Pension Plans [Member]	Dec. 31, 2013 Pension Plans [Member]	Mar. 31, 2014 Pension Plans [Member] AA [Member]	Apr. 15, 2014 Subsequent Event [Member] AA [Member]	Apr. 15, 2014 Subsequent Event [Member] Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 33	$ 385	$ 34	$ 33	$ 385	$ 34	$ 37	$ 37