Defined Benefit Pension And Other Postretirement Plans (Reconciliation Of Beginning And Ending Balances Of Plan Assets Classified As Level 3) (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Actual return on plan assets:
Fair value of plan assets at December 31	$ 1,800	$ 1,478
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at January 1	127	121
Actual return on plan assets:
Net realized gains/(losses)	16	3
Net unrealized gains/(losses)	16	(1)
Purchases	12	22
Sales	(34)	(18)
Fair value of plan assets at December 31	137	127
Private Equity [Member]
Actual return on plan assets:
Fair value of plan assets at December 31	57	56
Private Equity [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at January 1	56	55
Actual return on plan assets:
Net realized gains/(losses)	13	5
Net unrealized gains/(losses)	3	(3)
Purchases	7	12
Sales	(22)	(13)
Fair value of plan assets at December 31	57	56
Real Estate [Member]
Actual return on plan assets:
Fair value of plan assets at December 31	60	54
Real Estate [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at January 1	54	49
Actual return on plan assets:
Net realized gains/(losses)	3	(2)
Net unrealized gains/(losses)	10	2
Purchases	5	10
Sales	(12)	(5)
Fair value of plan assets at December 31	60	54
Other [Member]
Actual return on plan assets:
Fair value of plan assets at December 31	22	17
Other [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at January 1	17	17
Actual return on plan assets:
Net realized gains/(losses)	0	0
Net unrealized gains/(losses)	3	0
Purchases	0	0
Sales	0	0
Fair value of plan assets at December 31	$ 20	$ 17