Benefit Plans (Details 2) - USD ($) $ in Millions | 12 Months Ended | | |
Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2015 | Dec. 31, 2014 |
Pension benefits | | | | | |
Pension plans' assets | | | | | |
Actual return on plan assets | $ (43) | $ 540 | | | |
Defined Benefit Plan, Asset Allocation, Derivatives, Minimum | 105.00% | | | | |
Percentage of total plan assets for primary qualified employee | | | | 80.00% | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Actual percentage of plan assets | | | | 100.00% | 100.00% |
Notional amount of derivatives, maximum percentage of plan assets | 115.00% | | | | |
Total plan assets at fair value | | | | $ 5,501 | $ 5,993 |
Total plan assets at fair value, allocation (as a percent) | 100.00% | 100.00% | | | |
Securities lending obligation | | | | (167) | (234) |
Other net plan assets | | | | 19 | 24 |
Total reported plan assets | $ 5,783 | $ 5,602 | $ 5,602 | $ 5,353 | 5,783 |
Pension plan assets | | | | | |
Fair value of plan assets, beginning of year | 5,783 | 5,602 | | | |
Fair value of plan assets, end of year | $ 5,353 | $ 5,783 | $ 5,602 | | |
Expected weighted average long-term rate of return on plan assets (as a percent) | 7.33% | 7.36% | 7.75% | | |
Expected weighted average long-term rate of return on plan assets for the next fiscal year (as a percent) | 7.30% | | | | |
Expected weighted average long-term rate of return on primary employee plan assets for the next fiscal year (as a percent) | 7.75% | | | | |
Expected weighted average long-term rate of return on employee-agent plan assets for the next fiscal year (as a percent) | 5.75% | | | | |
Arithmetic average of the annual actual return on plan assets for the last 10 years (as a percent) | | | | 6.90% | |
Arithmetic average of the annual actual return on plan assets for the last 5 years (as a percent) | | | | 7.70% | |
Cash flows | | | | | |
Defined benefit pension plans, estimated employer contributions in next fiscal year | $ 129 | | | | |
Employer contribution | 125 | $ 49 | | | |
Participant contributions | $ 0 | $ 1 | | | |
Estimated future benefit payments | | | | | |
2,016 | | | | $ 341 | |
2,017 | | | | 372 | |
2,018 | | | | 388 | |
2,019 | | | | 436 | |
2,020 | | | | 472 | |
2021-2025 | | | | 2,569 | |
Total benefit payments | | | | 4,578 | |
Pension benefits | Quoted prices in active markets for identical assets (Level 1) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 342 | 1,116 |
Total plan assets at fair value, allocation (as a percent) | 6.20% | 18.60% | | | |
Pension benefits | Significant other observable inputs (Level 2) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 4,668 | 4,372 |
Total plan assets at fair value, allocation (as a percent) | 84.90% | 73.00% | | | |
Pension benefits | Significant unobservable inputs (Level 3) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 491 | 505 |
Total plan assets at fair value, allocation (as a percent) | 8.90% | 8.40% | | | |
Total reported plan assets | $ 505 | $ 690 | $ 946 | 491 | 505 |
Pension plan assets | | | | | |
Fair value of plan assets, beginning of year | 505 | 690 | 946 | | |
Actual return on plan assets: Relating to assets sold during the period | 1 | (5) | 15 | | |
Actual return on plan assets: Relating to assets still held at the reporting date | (24) | 12 | 28 | | |
Purchases, sales and settlements, net | 11 | (192) | (299) | | |
Net transfers in and/or (out) of Level 3 | (2) | 0 | 0 | | |
Fair value of plan assets, end of year | 491 | 505 | 690 | | |
Postretirement benefits | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total reported plan assets | 0 | 0 | | 0 | $ 0 |
Pension plan assets | | | | | |
Fair value of plan assets, beginning of year | 0 | | | | |
Fair value of plan assets, end of year | 0 | 0 | | | |
Cash flows | | | | | |
Employer contribution | 35 | 38 | | | |
Participant contributions | $ 19 | 19 | | | |
Estimated future benefit payments | | | | | |
2,016 | | | | 26 | |
2,017 | | | | 26 | |
2,018 | | | | 26 | |
2,019 | | | | 28 | |
2,020 | | | | 29 | |
2021-2025 | | | | 155 | |
Total benefit payments | | | | $ 290 | |
Equity securities | Pension benefits | | | | | |
Pension plans' assets | | | | | |
Percent of total equity securities in primary qualified employee plan | 86.00% | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Defined Benefit Plan, Target Plan Asset Allocations Range Minimum | 53.00% | | | | |
Defined Benefit Plan, Target Plan Asset Allocations Range Maximum | 63.00% | | | | |
Actual percentage of plan assets | | | | 60.00% | 41.00% |
Total plan assets at fair value | | | | $ 3,181 | $ 2,345 |
Equity securities | Pension benefits | Quoted prices in active markets for identical assets (Level 1) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 136 | 161 |
Equity securities | Pension benefits | Significant other observable inputs (Level 2) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 2,945 | 2,109 |
Equity securities | Pension benefits | Significant unobservable inputs (Level 3) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 100 | 75 |
Total reported plan assets | $ 75 | 237 | 314 | $ 100 | $ 75 |
Pension plan assets | | | | | |
Fair value of plan assets, beginning of year | 75 | 237 | 314 | | |
Actual return on plan assets: Relating to assets sold during the period | 1 | 2 | 3 | | |
Actual return on plan assets: Relating to assets still held at the reporting date | (5) | 2 | 18 | | |
Purchases, sales and settlements, net | 29 | (166) | (98) | | |
Net transfers in and/or (out) of Level 3 | 0 | 0 | 0 | | |
Fair value of plan assets, end of year | $ 100 | 75 | 237 | | |
Fixed income securities | Pension benefits | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Defined Benefit Plan, Target Plan Asset Allocations Range Minimum | 28.00% | | | | |
Defined Benefit Plan, Target Plan Asset Allocations Range Maximum | 37.00% | | | | |
Actual percentage of plan assets | | | | 30.00% | 50.00% |
Cash collateral from target asset allocation, investment allocation (as a percent) | 5.00% | | | | |
U.S. government and agencies | Pension benefits | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | $ 406 | $ 914 |
U.S. government and agencies | Pension benefits | Quoted prices in active markets for identical assets (Level 1) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 72 | 870 |
U.S. government and agencies | Pension benefits | Significant other observable inputs (Level 2) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 334 | 44 |
U.S. government and agencies | Pension benefits | Significant unobservable inputs (Level 3) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 0 | 0 |
Foreign government | Pension benefits | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | | 28 |
Foreign government | Pension benefits | Quoted prices in active markets for identical assets (Level 1) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | | 0 |
Foreign government | Pension benefits | Significant other observable inputs (Level 2) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | | 28 |
Foreign government | Pension benefits | Significant unobservable inputs (Level 3) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | | 0 |
Municipal | Pension benefits | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 7 | 14 |
Municipal | Pension benefits | Quoted prices in active markets for identical assets (Level 1) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 0 | 0 |
Municipal | Pension benefits | Significant other observable inputs (Level 2) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 0 | 0 |
Municipal | Pension benefits | Significant unobservable inputs (Level 3) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 7 | 14 |
Total reported plan assets | $ 14 | 18 | 129 | 7 | 14 |
Pension plan assets | | | | | |
Fair value of plan assets, beginning of year | 14 | 18 | 129 | | |
Actual return on plan assets: Relating to assets sold during the period | 0 | 0 | 7 | | |
Actual return on plan assets: Relating to assets still held at the reporting date | 0 | 0 | 1 | | |
Purchases, sales and settlements, net | (7) | (4) | (119) | | |
Net transfers in and/or (out) of Level 3 | 0 | 0 | 0 | | |
Fair value of plan assets, end of year | 7 | 14 | 18 | | |
Corporate | Pension benefits | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 1,215 | 1,834 |
Corporate | Pension benefits | Quoted prices in active markets for identical assets (Level 1) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 0 | 0 |
Corporate | Pension benefits | Significant other observable inputs (Level 2) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 1,205 | 1,822 |
Corporate | Pension benefits | Significant unobservable inputs (Level 3) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 10 | 12 |
Total reported plan assets | 12 | 18 | 10 | 10 | 12 |
Pension plan assets | | | | | |
Fair value of plan assets, beginning of year | 12 | 18 | 10 | | |
Actual return on plan assets: Relating to assets sold during the period | 0 | 0 | 5 | | |
Actual return on plan assets: Relating to assets still held at the reporting date | 0 | 0 | 0 | | |
Purchases, sales and settlements, net | 0 | (6) | 3 | | |
Net transfers in and/or (out) of Level 3 | (2) | 0 | 0 | | |
Fair value of plan assets, end of year | $ 10 | 12 | 18 | | |
RMBS | Pension benefits | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | | 115 |
RMBS | Pension benefits | Quoted prices in active markets for identical assets (Level 1) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | | 0 |
RMBS | Pension benefits | Significant other observable inputs (Level 2) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | | 115 |
RMBS | Pension benefits | Significant unobservable inputs (Level 3) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | | 0 |
Securities Pledged as Collateral [Member] | Pension benefits | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Defined Benefit Plan, Assets for Plan Benefits | | | | $ 152 | $ 217 |
Limited partnership interests | Pension benefits | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Defined Benefit Plan, Target Plan Asset Allocations Range Minimum | 0.00% | | | | |
Defined Benefit Plan, Target Plan Asset Allocations Range Maximum | 12.00% | | | | |
Actual percentage of plan assets | | | | 7.00% | 7.00% |
Short-term investments | Pension benefits | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Cash collateral from target asset allocation, investment allocation (as a percent) | 95.00% | | | | |
Total plan assets at fair value | | | | $ 296 | $ 309 |
Short-term investments | Pension benefits | Quoted prices in active markets for identical assets (Level 1) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 112 | 55 |
Short-term investments | Pension benefits | Significant other observable inputs (Level 2) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 184 | 254 |
Short-term investments | Pension benefits | Significant unobservable inputs (Level 3) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | $ 0 | $ 0 |
Short-term investments and other | Pension benefits | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Target asset allocation | 0.00% | | | | |
Actual percentage of plan assets | | | | 3.00% | 2.00% |
Real estate funds | Pension benefits | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | $ 104 | $ 154 |
Real estate funds | Pension benefits | Quoted prices in active markets for identical assets (Level 1) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 0 | 0 |
Real estate funds | Pension benefits | Significant other observable inputs (Level 2) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 0 | 0 |
Real estate funds | Pension benefits | Significant unobservable inputs (Level 3) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 104 | 154 |
Total reported plan assets | $ 154 | 197 | 214 | 104 | 154 |
Pension plan assets | | | | | |
Fair value of plan assets, beginning of year | 154 | 197 | 214 | | |
Actual return on plan assets: Relating to assets sold during the period | 0 | (3) | 0 | | |
Actual return on plan assets: Relating to assets still held at the reporting date | (12) | 6 | 11 | | |
Purchases, sales and settlements, net | (38) | (46) | (28) | | |
Net transfers in and/or (out) of Level 3 | 0 | 0 | 0 | | |
Fair value of plan assets, end of year | 104 | 154 | 197 | | |
Private equity funds | Pension benefits | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 237 | 218 |
Private equity funds | Pension benefits | Quoted prices in active markets for identical assets (Level 1) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 0 | 0 |
Private equity funds | Pension benefits | Significant other observable inputs (Level 2) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 0 | 0 |
Private equity funds | Pension benefits | Significant unobservable inputs (Level 3) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 237 | 218 |
Total reported plan assets | 218 | 211 | 199 | 237 | 218 |
Pension plan assets | | | | | |
Fair value of plan assets, beginning of year | 218 | 211 | 199 | | |
Actual return on plan assets: Relating to assets sold during the period | 0 | (4) | 0 | | |
Actual return on plan assets: Relating to assets still held at the reporting date | (8) | 4 | (2) | | |
Purchases, sales and settlements, net | 27 | 7 | 14 | | |
Net transfers in and/or (out) of Level 3 | 0 | 0 | 0 | | |
Fair value of plan assets, end of year | 237 | 218 | 211 | | |
Hedge funds | Pension benefits | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 33 | 32 |
Hedge funds | Pension benefits | Quoted prices in active markets for identical assets (Level 1) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 0 | 0 |
Hedge funds | Pension benefits | Significant other observable inputs (Level 2) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 0 | 0 |
Hedge funds | Pension benefits | Significant unobservable inputs (Level 3) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 33 | 32 |
Total reported plan assets | 32 | 9 | 80 | 33 | 32 |
Pension plan assets | | | | | |
Fair value of plan assets, beginning of year | 32 | 9 | 80 | | |
Actual return on plan assets: Relating to assets sold during the period | 0 | 0 | 0 | | |
Actual return on plan assets: Relating to assets still held at the reporting date | 1 | 0 | 0 | | |
Purchases, sales and settlements, net | 0 | 23 | (71) | | |
Net transfers in and/or (out) of Level 3 | 0 | 0 | 0 | | |
Fair value of plan assets, end of year | $ 33 | $ 32 | $ 9 | | |
Cash and cash equivalents | Pension benefits | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 22 | 34 |
Cash and cash equivalents | Pension benefits | Quoted prices in active markets for identical assets (Level 1) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 22 | 34 |
Cash and cash equivalents | Pension benefits | Significant other observable inputs (Level 2) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | 0 | 0 |
Cash and cash equivalents | Pension benefits | Significant unobservable inputs (Level 3) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | $ 0 | 0 |
Free Standing Derivative Assets | Pension benefits | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | | (1) |
Free Standing Derivative Assets | Pension benefits | Quoted prices in active markets for identical assets (Level 1) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | | (1) |
Free Standing Derivative Assets | Pension benefits | Significant other observable inputs (Level 2) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | | 0 |
Free Standing Derivative Assets | Pension benefits | Significant unobservable inputs (Level 3) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | | 0 |
Free Standing Derivatives Liabilities | Pension benefits | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | | (3) |
Free Standing Derivatives Liabilities | Pension benefits | Quoted prices in active markets for identical assets (Level 1) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | | (3) |
Free Standing Derivatives Liabilities | Pension benefits | Significant other observable inputs (Level 2) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | | 0 |
Free Standing Derivatives Liabilities | Pension benefits | Significant unobservable inputs (Level 3) | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Total plan assets at fair value | | | | | $ 0 |
Equity securities | Fixed income securities | Pension benefits | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Actual percentage of plan assets | | | | 3.00% | 3.00% |
Equity securities | Derivatives | Pension benefits | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Actual percentage of plan assets | | | | | 9.00% |
Equity securities | Private equity funds | Pension benefits | | | | | |
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets | | | | | |
Actual percentage of plan assets | | | | 2.00% | 1.00% |